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Dust deposition poses a significant challenge in the implementation of photovoltaic panels (PV) especially in hot and dusty environments, such as the Middle East and North Africa (MENA) region. This issue leads to progressive degradation of PV efficiency and output power. In this context, this research work aims to improve PV performance by developing self-cleaning sprays as a preventative solution. Different concentrations of SnO2 and TiO2 nanoceramics were dispersed in isopropyl alcohol solvent to reduce the mixture's viscosity and facilitate smooth spraying on solar panels, whose efficiency was continually assessed in outdoor conditions. Although less commonly used for this application, the nano-SnO2 was selected for the purpose of enhancing the surface hydrophobicity, whereas nano-TiO2 was included for its favorable photocatalytic properties. Polydimethylsiloxane (PDMS) oil, known for its self-cleaning characteristic, was served as the base material in the developed sprays. The described blend of materials represents a novel combination. The results indicated that 2.5% nano-SnO2 and 2.5% nano-TiO2 in PDMS oil enhanced efficiency by 5.4% compared to a non-sprayed panel after five weeks of outdoor exposure. This efficiency gain was experimentally justified and attributed to the spray's ability to achieve a water contact angle (WCA) of 100.6°, forming a hydrophobic surface conducive to self-cleaning. Further characterization results, including photocatalysis and zeta potential have been gathered and analyzed. [ABSTRACT FROM AUTHOR]

AbstractA high-sensitivity temperature sensor based upon an optical fiber Fabry-Perot interferometer (FPI) filled with polydimethylsiloxane (PDMS) is reported that employed a single mode fiber (SMF) and a hollow core fiber (HCF) to enhance the sensitivity. The sensing characteristics were investigated from 20 °C to 40 °C. The experimental results demonstrate that the sensor is sensitive to temperature due to the high thermal optical coefficient (TOC) and high thermal expansion coefficient (TEC) of PDMS, achieving a high sensitivity of 2.155 nm/°C. The designed sensor shows great potential for high-precision temperature sensing applications due to its high sensitivity, compact structure, and simple preparation. [ABSTRACT FROM AUTHOR]

Laser micromachining has been used as an alternative to producing microfluidics structures and simplifying the conventional soft lithography process. In this paper we characterize the excimer laser micromachining parameters and demonstrate its application by producing several microfluidic structures in polydimethylsiloxane (PDMS). The parameters include the number of laser pulses, laser energy and rectangular variable aperture (RVA) in both x- and y-directions. We found that the laser energy and pulse rate affect the depth of micromachining d channels, while RVA in both x- and y-directions affects the width of the channels. Repetition of laser scan does not change the channel width but significantly changes the channel depth. Proper adjustment for laser energy and pulse rate is required to fabricate a desired channels depth. In order to demonstrate the microfabrication capability of an excimer laser with the optimal operating parameters, several microfluidic structures were micromachining d into PDMS with a KrF excimer laser. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have emerged as viable micro power sources for an array of applications. Since their inception in 2012, TENGs have been the subject of significant advancements in terms of structural design and the development of friction materials. Despite these advancements, the complexity of their structural designs and the use of costly friction materials hinder their practical application. This study introduces a simplified TENG model utilizing an economical composite film of fullerene carbon soot (FS)-doped polydimethylsiloxane (PDMS) (FS-TENG). It confirms the FS-TENG's ability to convert mechanical energy into electrical energy, as demonstrated through experimental validation. The generated electricity by the FS-TENG can power devices such as light-emitting diodes (LEDs), digital watches, kitchen timers, and sports stopwatches, highlighting its efficiency. This research enhances the development of TENGs featuring low-cost, streamlined structures for sustainable and autonomous energy sensing applications. [ABSTRACT FROM AUTHOR]

This work showcases the production of flexible polydimethylsiloxane/multiwalled carbon nanotube (PDMS/MWCNT) composites with multilayer structures via the glucose template method followed by vacuum‐assisted filtration and hot pressing. The properties of the single‐layer and multilayer composites have been systematically investigated. In the X‐band, thanks to the ohmic loss, the interfacial polarization loss at the interfaces and the multiple reflections between PDMS/MWCNT layers, the 5‐layer PDMS/MWCNT composites achieves 65.9 dB. Furthermore, all multilayer PDMS/MWCNT composites present a high retention rate of about of 90% after repeated bending with curvature radius of 1.8 mm at a frequency of 1 cycle per 2 s for 1000 times. Highlights: The PDMS/MWCNT composites are fabricated by the glucose template method.The 5‐layer PDMS/MWCNT composites can reach 65.9 dB in X‐band.The PDMS/MWCNT composites present high stability even after repeated bending. [ABSTRACT FROM AUTHOR]

Recently, the manufacturing of porous polydimethylsiloxane (PDMS) with engineered porosity has gained considerable interest due to its tunable material properties and diverse applications. An innovative approach to control the porosity of PDMS is to use transient liquid phase water to improve its mechanical properties, which has been explored in this work. Adjusting the ratios of deionized water to the PDMS precursor during blending and subsequent curing processes allows for controlled porosity, yielding water emulsion foam with tailored properties. The PDMS-to-water weight ratios were engineered ranging from 100:0 to 10:90, with the 65:35 specimen exhibiting the best mechanical properties with a Young's Modulus of 1.17 MPa, energy absorption of 0.33 MPa, and compressive strength of 3.50 MPa. This led to a porous sample exhibiting a 31.46% increase in the modulus of elasticity over a bulk PDMS sample. Dowsil SE 1700 was then added, improving the storage capabilities of the precursor. The optimal storage temperature was probed, with −60 °C resulting in great pore stability throughout a three-week duration. The possibility of using these water emulsion foams for paste extrusion additive manufacturing (AM) was also analyzed by implementing a rheological modifier, fumed silica. Fumed silica's impact on viscosity was examined, revealing that 9 wt% of silica demonstrates optimal rheological behaviors for AM, bearing a viscosity of 10,290 Pa·s while demonstrating shear-thinning and thixotropic behavior. This study suggests that water can be used as pore-formers for PDMS in conjunction with AM to produce engineered materials and structures for aerospace, medical, and defense industries as sensors, microfluidic devices, and lightweight structures. [ABSTRACT FROM AUTHOR]

This work investigates the friction between polydimethylsiloxane (PDMS) and silicon oxide (SiOx) in single asperity sliding contact by atomic force microscopy (AFM). Two friction dependences on the normal force are identified: a tensile regime and a compressive regime of normal forces. In the compressive regime, friction is governed by the shear deformation and rupture of junctions between PDMS and SiOx. In this case, the shear strength τ ≈ 10 MPa is comparable with the cohesive strength of PDMS under compressive loading. In contrast, friction in the tensile regime is also affected by the elongation of the junctions. The single SiOx-asperity follows a stick-slip motion on PDMS in both normal force regimes. Statistical analysis of stick-slip as a function of the normal force allows determining the necessary amount of energy to break a SiOx/PDMS junction. Friction between a SiOx-asperity and a PDMS surface can be rationalized based on an energy criterion for the deformation and slippage of nanometer-scale junctions. [ABSTRACT FROM AUTHOR]

We investigate the combined effects of surface diffraction and total internal reflection (TIR) in the design of 3-dimensional materials exhibiting distinct structural colour on various facets. We employ mechanical wrinkling to introduce surface diffraction gratings (from the nano to the micron scales) on one face of an elastomeric rectangular parallelepiped-shaped slab and explore the roles, in the perceived colours, of wrinkling pattern, wavelength, the directionality of incident light and observation angles. We propose a simple model that satisfactorily accounts for all experimental observations. Employing polydimethylsiloxane (PDMS), which readily swells in the presence of various liquids and gases, we demonstrate that such multifaceted colours can respond to their environment. By coupling a right angle triangular prism with a surface grating, we demonstrate the straightforward fabrication of a so-called GRISM (GRating + prISM). Finally, using a range of examples, we outline possibilities for a predictive material design using multi-axial wrinkling patterns and more complex polyhedra. [ABSTRACT FROM AUTHOR]

The research aim is to develop multilayered capacitive film pressure sensors with dot and micro-pillar array, having high transparency, sensitivity, and flexibility by utilizing polydimethylsiloxane (PDMS) and the conductive polymer, poly(3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS)" as the primary components. The results reveal that the transmittance values of the multilayered capacitive film sensors with dot array vary with their thickness, achieving values of 76.39 %, 72.06 %, and 65.39 % at a center wavelength of 550 nm and demonstrating the effective capacitive sensing response in the pressure range of 0–750 kPa. Notably, the micro-pillar array multilayered capacitive film sensor shows high sensitivity of 0.025 kPa−1 in the pressure range of 0–100 kPa and a clear trend of capacitance change around 60 kPa. It achieves the highest sensitivity of 0.05 kPa−1 within the 0–10 kPa pressure range. The stability of the multilayered capacitive film sensor is examined by applying compressive forces of 0.5 N, 1.0 N, and 1.5 N in a suspended state, resulting in a maximum rate of change reaching 104.7 % compared to the initial capacitance value. Additionally, the multilayered capacitive film sensors demonstrate good stability under cyclic pressures of 0.5 N, 1.0 N, and 1.5 N. The novel multilayered capacitive film sensor offers specific promising potentials for various applications in the fields of wearable, medical devices, and human-machine interfaces. [Display omitted] • The transmittance of dot-array film sensor is 72.06±0.49 with 0.17±0.01 mm thick at wavelength of 550 nm. • Dot-array film sensor demonstrates higher variations with a sensitivity of 0.01 kPa−1 in the 0–100 kPa pressure range. • Beyond 200 kPa, capacitance change of dot-array film sensor tends to reach a maximum capacitance change rate of 123.28%. • The sensitivity of micro-pillar array film sensor is 0.025 kPa−1 in the 0–100 kPa range. • The micro-pillar array film sensor exhibits high stability subjecting to external bending and long-term compressive test. [ABSTRACT FROM AUTHOR]

The surface stiffness of the microenvironment is a mechanical signal regulating biofilm growth without the risks associated with the use of bioactive agents. However, the mechanisms determining the expansion or prevention of biofilm growth on soft and stiff substrates are largely unknown. To answer this question, we used PDMS (polydimethylsiloxane, 9–574 kPa) and HA (hyaluronic acid gels, 44 Pa–2 kPa) differing in their hydration. We showed that the softest HA inhibited Escherichia coli biofilm growth, while the stiffest PDMS activated it. The bacterial mechanical environment significantly regulated the MscS mechanosensitive channel in higher abundance on the least colonized HA-44Pa, while Type-1 pili (FimA) showed regulation in higher abundance on the most colonized PDMS-9kPa. Type-1 pili regulated the free motion (the capacity of bacteria to move far from their initial position) necessary for biofilm growth independent of the substrate surface stiffness. In contrast, the total length travelled by the bacteria (diffusion coefficient) varied positively with the surface stiffness but not with the biofilm growth. The softest, hydrated HA, the least colonized surface, revealed the least diffusive and the least free-moving bacteria. Finally, this shows that customizing the surface elasticity and hydration, together, is an efficient means of affecting the bacteria's mobility and attachment to the surface and thus designing biomedical surfaces to prevent biofilm growth. [ABSTRACT FROM AUTHOR]

In our recent study, we fabricated a pump/tube-connection-free microchip comprising top and bottom polydimethylsiloxane (PDMS) slabs to produce monodispersed water-in-oil droplets in a fully automated, fluid-manipulation fashion. All microstructures required for droplet production were directly patterned on the surfaces of the two PDMS slabs through CO2-laser micromachining, facilitating the fast fabrication of the droplet-production microchips. In the current extension study, we replaced the bottom PDMS slab, which served as a microfluidic layer in the microchip, with a poly(methyl methacrylate) (PMMA) slab. This modification was based on our idea that the bottom PDMS slab does not contribute to the automatic fluid manipulation and that replacing the bottom PDMS slab with a more affordable and accessible, ready-to-use polymer slab, such as a PMMA, would further facilitate the rapid and low-cost fabrication of the connection-free microchips. Using a new PMMA/PDMS microchip, we produced water-in-oil droplets with high degree of size-uniformity (a coefficient of variation for droplet diameters of <5%) without a decrease in the droplet production rate (~270 droplets/s) as compared with that achieved via the previous PDMS/PDMS microchip (~220 droplets/s). [ABSTRACT FROM AUTHOR]

Since the important applications in multiple fields, research on temperature sensors based on surface plasmon resonance (SPR) technology is receiving increasing attention. Therefore, a SPR-based temperature sensor consisting of temperature-sensitive material of polydimethylsiloxane (PDMS) and titanium dioxide (TiO2) forming a bi-layer silver structure has been proposed and investigated in this work. As a solid medium with a high thermo-optic coefficient, the PDMS can significantly improve the temperature sensitivity of the sensor. By adjusting the thickness of each layer of the TiO2-Ag-TiO2-Ag-PDMS sensing structure, the optimal thickness combination of the structure can be obtained. The thickness of the TiO2 layer between two silver layers and the thickness of the PDMS layer can adjust the position of the resonance angle. Adding a monolayer of WS2 upon the PDMS layer can further improve the sensitivity. With an incident with monochromatic light at 632.8 nm, the maximum sensitivity of the structure in the range of 275–360 K and 321–360 K is − 0.094°/K (air) and − 0.129°/K (ethanol), respectively, maintaining high linearity in the range of 310–340 K. The temperature sensitivity also remains high linearity at wavelengths of 620 nm and 680 nm. The proposed sensor structure exhibits excellent sensitivity and figures of merit in the field of sensing temperature. [ABSTRACT FROM AUTHOR]

Biocompatibility, flexibility and durability make polydimethylsiloxane (PDMS) membranes top candidates in biomedical applications. CellDrum technology uses large area, <10 µm thin membranes as mechanical stress sensors of thin cell layers. For this to be successful, the properties (thickness, temperature, dust, wrinkles, etc.) must be precisely controlled. The following parameters of membrane fabrication by means of the Floating-on-Water (FoW) method were investigated: (1) PDMS volume, (2) ambient temperature, (3) membrane deflection and (4) membrane mechanical compliance. Significant differences were found between all PDMS volumes and thicknesses tested (p < 0.01). They also differed from the calculated values. At room temperatures between 22 and 26 °C, significant differences in average thickness values were found, as well as a continuous decrease in thicknesses within a 4 °C temperature elevation. No correlation was found between the membrane thickness groups (between 3–4 µm) in terms of deflection and compliance. We successfully present a fabrication method for thin bio-functionalized membranes in conjunction with a four-step quality management system. The results highlight the importance of tight regulation of production parameters through quality control. The use of membranes described here could also become the basis for material testing on thin, viscous layers such as polymers, dyes and adhesives, which goes far beyond biological applications. [ABSTRACT FROM AUTHOR]

This study aims to develop microcapsules that can be used as room‐temperature self‐healing agents in silicone‐based matrices. A telechelic reactive silanol‐terminated polydimethylsiloxane (PDMS) as the healing agent, was selected to ensure the homogeneity of the polymeric matrix and encapsulated in poly(melamine‐urea‐formaldehyde) shells through an in‐situ emulsion polymerization technique. To catalyze the polycondensation reaction of the healing agent, dibutyltin dilaurate (DBTL) was encapsulated within the same type of polymeric shell. The synthesized microcapsules were characterized using Fourier‐transform infrared spectrometry, optical microscopy, scanning electron microscopy (SEM), and differential scanning calorimetry. The analyses confirmed that the spherical microcapsules with an average size of 56 μm for PDMS‐MUF microcapsules and 42 μm for DBTL‐MUF microcapsules, with a shell wall thickness of 100–200 nm, and good thermal stability were formed. Therefore, the two‐component self‐healing silicone composite was successfully developed using 10:1.2 wt% PDMS: DBTL microcapsules within the silicone matrix. SEM showed the self‐healing ability of the silicone matrix by observing the successful healing of microcracks at room temperature. Tensile and trouser tear tests were adopted to assess the self‐healing performance of the elastomeric matrix, showing the self‐healing efficiencies of 67% and 55%, respectively. [ABSTRACT FROM AUTHOR]

As polydimethylsiloxane (PDMS) is a high elastic material rather than a hard and brittle material at room temperature, the processing efficiency is very low or even zero by using micro-abrasive air jet to process it, and a large number of abrasive particles will be embedded into the surface of PDMS. When the cooling of PDMS is incomplete, that is, in the transition state between the high elastic state and the glass state, the machining of PDMS using cryogenic micro-abrasive air jet will still have a very serious abrasive embedding phenomenon, resulting in poor processing effect. To solve this problem, this paper uses ANSYS Fluent software to conduct heat transfer simulation analysis on PDMS to obtain the internal temperature change of PDMS, so as to calculate the cooling rate in the depth direction of PDMS. At the same time, the same process parameters are used to process micro holes on the surface of PDMS, and the maximum average erosion processing rate in the depth direction of PDMS can be calculated. Finally, it is found that the cooling rate is much faster than the erosion processing rate. According to the analysis results of heat transfer simulation, single-factor experiments are carried out to explore the effect of feed speed v, processing distance D, erosion angle α, and processing pressure p on the processing performance of PDMS, which provides an important reference for further research. [ABSTRACT FROM AUTHOR]

A droplet generator with an embedded 3D balloon actuator around a flow-focusing junction is realized to adjust the size of the droplets as required with only one element. The 3D actuator encircling the orifice causes a geometric deformation due to pneumatic pressure, which controls the orifice and thus the sizes of the droplets. The orifice and actuator are designed to have triangular cross-sections with the largest possible reduction in hydraulic diameters under the same pneumatic pressure. We empirically demonstrated that, compared with typical fixed orifice structures, droplet generators with variable orifices reduce the droplet size without changing the flow rate and can even be adjusted to a wider range of 259.3 %. The devices were fabricated by the 3D-printed soluble mold technique to achieve a fully 3D structure within a single body of polydimethylsiloxane that is unattainable by conventional standard microfabrications as well as a non-bonding structure without any leakage. [ABSTRACT FROM AUTHOR]

The complexity of the subsurface contaminated by chlorinated solvents such as trichloroethylene (TCE) makes it challenging to gain a complete understanding of contamination distribution and establish a conceptual site model (CSM). High-resolution vertical contaminant concentration profiling across both the unsaturated zone and the saturated aquifer is desirable for mapping the distribution of contamination. A Fick's law-based polydimethylsiloxane (PDMS) dialysis passive sampler was developed and evaluated on a field scale for its potential application. This study tests the passive sampler at two TCE contaminated sites, and the sampling results were compared with the results from different sampling methods based on the relative percent difference. The PDMS dialysis passive sampler obtained more representative soil gas concentrations in the unsaturated zone than a portable monitoring and sampling device, which caused soil gas flow disturbance by soil gas pumping during sample collection. In the saturated aquifer sampling, the results obtained by the PDMS dialysis passive sampler correlated well with those obtained by a commercial polyethylene passive diffusion bag, and exhibited higher sensitivity under low TCE concentration conditions. Furthermore, the PDMS dialysis passive samplers were densely deployed inside each monitoring well at multiple depths, at two sites, to achieve high-resolution monitoring across the unsaturated zone and saturated aquifer. Based on the PDMS dialysis sampler data, a more comprehensive three-dimensional CSM was systematically established. [Display omitted] • A Fick's Law based PDMS dialysis sampler was developed and tested at a TCE contaminated site. • The sampler can be used for measuring contaminants in the unsaturated zone and saturated aquifers. • The sampler is less susceptible to gas disturbance than other sampling methods. • The sampler exhibits high sensitivity to low contaminant concentrations. • The samplers can be densely deployed inside a monitoring well at multiple depths. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane (PDMS) is a polymer that has attracted the attention of researchers due to its unique properties such as transparency, biocompatibility, high flexibility, and physical and chemical stability. In addition, PDMS modification and combination with other materials can expand its range of applications. For instance, the ability to perform superhydrophobic coating allows for the manufacture of lenses. However, many of these processes are complex and expensive. One of the most promising modifications, which consists of the development of an interchangeable coating, capable of changing its optical characteristics according to some stimuli, has been underexplored. Thus, we report an experimental study of the mechanical and optical properties and wettability of pure PDMS and of two PDMS composites with the addition of 1% paraffin or beeswax using a gravity casting process. The composites’ tensile strength and hardness were lower when compared with pure PDMS. However, the contact angle was increased, reaching the highest values when using the paraffin additive. Additionally, these composites have shown interesting results for the spectrophotometry tests, i.e., the material changed its optical characteristics when heated, going from opaque at room temperature to transparent, with transmittance around 75%, at 70 ◦C. As a result, these materials have great potential for use in smart devices, such as sensors, due to its ability to change its transparency at high temperatures. [ABSTRACT FROM AUTHOR]

The study of CO2/N2 separation by supported ionic liquid membranes (SILMs) based on polymeric membrane with ceramic support is presented. The SILMs have been developed by impregnation of the ceramic support of commercial polydimethylsiloxane (PDMS) membrane with ionic liquid: 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]). The objective was to investigate the CO2/N2 separation enhancement and stability of the prepared SILMs. The effects of the feed temperature, pressure difference and impregnation method on performance of developed SILMs were analyzed. Two methods of impregnation were used: coating and soaking. The comparison of separation efficiency of the SILMs prepared by the coating method shows good long-term stability and very high CO2/N2 selectivities up to 152. The obtained results present an inexpensive alternative in the selective CO2/N2 separation by SILMs. The comparison with Robeson upper bond correlation and literature data shows that applying an appropriate ionic liquid and impregnating method to the PDMS membrane results in significant improvement of separation performance. [ABSTRACT FROM AUTHOR]

The permittivity response from 0.5 to 40 GHz of ethyl acetate (C4H8O2), ethylene glycol (CH2OH)2, castor oil (C57H104O9), liquid paraffin, and other fluids commonly used for microwave microfluidic antennas and circuits is reported. The response of selected polymer solids, such as polydimethylsiloxane (PDMS), acrylonitrile butadiene styrene (ABS), acrylic, nylon, and others, used in microfluidics and 3-D printing of microwave structures was also studied from 0.5 to 20 GHz. Permittivity measurements were taken with a coaxial probe. Using a nonlinear least-squares fitting routine, the Cole–Cole dielectric relaxation model parameters are found for each material under test, thereby providing an analytic expression for their permittivity response. [ABSTRACT FROM AUTHOR]

In recent years, forming a 3D microfluidic channels on the electrical non-conductive material such as Polydimethylsiloxane (PDMS) in the micro-electromechanical system (MEMS) and medical applications is of great interest. Lithography is the most know process to create patterns on the PDMS however there are a few drawbacks to this process such as high operational cost and time, and sidewall angle. In all applications, the quality of the micro-channel surface determines the performance of it. In this research as innovatively the electrochemical discharge milling (ECDM) which is known for lower operational cost and proper material removal rate (MRR; i.e. process time), and is capable of creating patterns on electrical non-conductive material, was used to form a micro-channel on the PDMS. To that end, the effect of process parameters such as electrolyte concentration, feed rate and cutting speed and voltage on the surface roughness and surface integrity deeply investigated. It was observed that ECDM is capable of creating patterns on the PDMS with surface integrity which is comparable with the lithography microchannel. It is also observed that decreasing the rotational speed from 10000 to 0rpm results in increasing the surface roughness 2 to 4 times. This happens due to the increasing the thickness of the gas film around the tool, and subsequently increasing the flying sparks which results in higher surface roughness. Increasing the Voltage from 38 to 42V results in 36% enhancement of surface roughness. The 25% electrolyte concentration results in lower surface roughness. [ABSTRACT FROM AUTHOR]

The green synthesis of nanoparticles is of considerable interest because it is eco-friendly, cost-effective, biocompatible, and non-toxic. Split pulse extract was used as a reducing/capping agent for the synthesis of titanium dioxide (TiO2) nanoparticles. Green synthesized nanoparticles were embedded in the polydimethylsiloxane (PDMS) membrane by using a solution casting technique to develop a nanocomposite. This thin film was characterized using Fourier transform infrared spectroscopy, scanning probe microscopy, high-resolution scanning electron microscopy, ultraviolet-visible spectroscopy, and contact angle analysis. The antibacterial property of the TiO2/PDMS nanocomposite was examined, and the results showed excellent antibacterial activity of TiO2/PDMS compared to PDMS without nanoparticles. The nanocomposite film exhibited antibacterial activity against Gram-positive and Gram-negative bacteria in the presence of TiO2 nanoparticles in the polymer. Here, different weight percentages of TiO2 nanoparticles, i.e. 0%, 7%, 10%, and 13%, were loaded on the PDMS surface to enhance its antibacterial activity. The green synthesis of TiO2 nanoparticles embedded in PDMS and their suitability for antibacterial activity are reported for the first time. [ABSTRACT FROM AUTHOR]

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Polydimethylsiloxane (PDMS), even though widely used in microfluidic applications, its hydrophobic nature restricts its utility in some cases. To address this, PDMS may be used in conjunction with a hydrophilic material. Herein, the PDMS surface is modified by plasma treatment followed by cross-linking with the cataractous eye protein isolate (CEPI). CEPI-PDMS composites are prepared at three pH and the effects of CEPI on the chemical, physical, and electrical properties of PDMS are extensively investigated. The cross-linking between PDMS and the protein are confirmed by FTIR, and the contact angle measurements indicate the improved hydrophilic nature of the composite films as compared to PDMS. Atomic Force Microscopy results demonstrate that the surface roughness is enhanced by the incorporation of the protein and is a function of the pH. The effective elastic modulus of the composites is improved by the incorporation of protein into the PDMS matrix. Measurements of the dielectric properties of these composites indicate that they behave as capacitors at lower frequency range while demonstrating resistive characteristics at higher frequency. These composites provide preliminary ideas in developing flexible devices for potential applications in diverse areas such as energy storage materials, and thermo-elective wireless switching devices. [ABSTRACT FROM AUTHOR]

Herein, a transparent and reproducible substrate, fabricated using polydimethylsiloxane (PDMS) laminated with self-assembled Ag nanoparticles (Ag NPs), was employed as a universal surface-enhanced Raman scattering (SERS) substrate for the detection of targets with various matrices. The Ag NPs were assembled in a two-dimensional manner via a self-assembly technique. Due to the electrostatic interaction between the Ag NPs, the reproducibility of the assembly was ensured by the fixed density of the assembled Ag NPs at saturated assembly states. The assembled pattern and plasmon resonance of the Ag NPs were well preserved during the molding and curing of PDMS. As a result, the Ag NP laminated PDMS film exhibited a SERS effect to the adsorbed p-aminothiophenol comparable to that of the assembled Ag NPs on a glass slide. Extra SERS enhancement was achieved by construction of a Ag (PDMS)/molecule/Ag (glass) configuration due to the electromagnetic coupling between the Ag NPs. The Raman scattering of 4-mercaptobenzoic acid and benzotriazole modified on the surfaces of a smooth Au electrode and copper foil, respectively, was detected with the aid of the Ag NP-laminated PDMS film. Furthermore, malachite green dispersed in a KBr solid matrix was quantitatively determined with a detection limit of 0.5 μg/g. It is suggested that the SERS enhancement and consequential SERS detection sensitivity of the target molecules may be further maximized by adjusting the distance between the target molecules and the Ag NPs laminated on the PDMS film. [ABSTRACT FROM AUTHOR]

Prediction of the temporal water wetting of water/PDMS interface in the presence of 3D interconnected pore network, surfactant, and combination of both. Diverse surface/bulk treatments have been introduced to overcome the interfacial limitations of pristine (or untreated) PDMS, thus extending the possible applications of PDMS in micro/nano device development. Despite of extensive efforts, the temporal wetting change of PDMS induced by surface/bulk treatments still remains incompletely understood. We prepared 3 kinds of physicochemically treated PDMS blocks using widely used surface/bulk treatments–3D interconnected pore network formation, biocompatible surfactant (i.e., Silwet L-77) addition, and combination of both. Their wetting nature was characterized by measuring the time profile of water contact angle. A 3D interconnected pore network formation produced a time-invariant decrease in PDMS wettability; a surfactant addition increased the PDMS wettability in a time-variant way; a combination of pore network formation and surfactant addition had a combined effect. The measurement led to the successful development of a model for predicting the temporal wetting change in PDMS caused by variances in pore size and surfactant concentration. The accuracy of our model was verified by comparing experimental results with model predictions. This model will result in better understanding of polymer interface. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract This study explored a click method of using filter paper (FP) and a polydimethylsiloxane (PDMS) polymer coating solution to prepare a cost-effective volatile organic compound (VOC) preconcentrating sampler. This is the first report of successfully cross-linking a hydrophobic polymer with cellulose in filter paper via a sol-gel method and its application to the preconcentration of headspace VOCs. Our Fourier transform infrared spectroscopy analysis results of the PDMS-coated filter paper (FP-PDMS) showed that the spectral intensity of the alcoholic O H stretch from FP or PDMS was reduced by the addition of trifluoroacetic acid to the PDMS solution, which indicated that an alcohol group in PDMS underwent cross-linking with another alcohol group in the cellulose or PDMS. Scanning electron microscopy (SEM) images of FP-PDMS revealed that the fibrous structure of the FP surface was partially compromised by the PDMS coating, but the porous structure of FP is partially preserved. The addition of the PDMS coating to the FP increased the efficiency of the preconcentration of headspace VOCs evaporated from water. Three types of carbon additives, activated carbon, graphite, and fullerene, were tested in order to evaluate their effects on headspace VOC preconcentration efficiency for FP-PDMS, with the addition of activated carbon found to provide the largest increase in preconcentration efficiency. The extent of the enhancement of the preconcentration efficiency provided by the carbon additives varied with the VOC compounds, as well the type of carbon additive. The FP-PDMS both with and without activated carbon can be used to successfully preconcentrate benzene, toluene, ethylbenzene, and m-xylene from sub-ppb water samples with the headspace gas sampling method. Graphical abstract Unlabelled Image Highlights • Polymer-coated filter paper was developed for sampling volatile organic compounds. • The sampler was applicable to headspace analysis for sub-ppb water samples. • Adding activated carbon to the sampler enhanced the preconcentration efficiencies. [ABSTRACT FROM AUTHOR]

In this study, polydimethylsiloxane (PDMS) was applied for overall hydrophobic modification of alkali-activated slag (AAS) mortars aiming to reduce its high water sorptivity. The effects of the amount and viscosity of PDMS on the water absorption characteristics and mechanical properties of AAS mortars were investigated. Meanwhile, MIP, the surface contact angle of AAS mortars and SEM-EDS, Inverse gas chromatography (IGC), FT-IR, XRD of hardened AAS pastes were performed for analyzing the modification mechanisms. The results indicated that the water sorptivity of PDMS-modified AAS mortar decreased by 90 %, and the contact angle of the inner surface increased from 14° to 128° when the dosage of PDMS reached 8 % (by weight of binder). The main modification mechanisms of PDMS in AAS system can be summarized as: Firstly, the formation of hydrophobic coatings on the surface due to the cross-linking reaction between C-S-H gel and PDMS reduces the surface energy and the hydrophilicity of hardened AAS pastes, achieving chemical modification; Secondly, the hierarchical structures formed by micro papillary increases the surface roughness, thus enhancing the hydrophobic effect further through physical modification. Moreover, the coarsening of capillary pores also reduces the capillary force during water absorption process. Meanwhile, the addition of PMDS maintains comparable strength development of AAS mortars, which is beneficial for the practical application. • PDMS-modified AAS mortars converted from hydrophilic to hydrophobic porous materials. • A 90 % reduction of water sorptivity of mortars was achieved by addition of PDMS. • The hardened PDMS-modified AAS pastes possessed lotus-leaf-like microstructure formed by micro papillary. • The PDMS-modified mortar exhibited stable strength development. [ABSTRACT FROM AUTHOR]

Focused ion beam (FIB) has been invented for several decades and widely utilized as a result of rapid development of integrated circuit industry and nanotechnology. Together with high resolution scanning electron microscopy (SEM), FIB can realize controllable micro-nano fabrication of metals and semiconductors. However, it is very difficult to guarantee the machining precision and quality when we extend the application to flexible materials. Severe damages such as the local thermal effect and chemical evolution will be induced with high-energy FIB bombarding on the flexible sample, so current models of FIB fabrication are no longer valid. In this paper, a practical 3-D FIB power deposition model was developed for studying the temperature rising mechanism and the according thermal evolution to realize controllable high-precision fabrication of flexible samples. Based on theories of ion transportation and ion-solid interaction, a new 3-D power deposition model including ion energy, aberrations, and Coulomb force among ions was built with Runge-Kutta method and Monte Carlo simulation. Thermal evolution of the representative flexible sample polydimethylsiloxane (PDMS) was studied with the finite element COMSOL-Multiphysics according to Fourier law of heat conductivity. The new model was improved by studying thermal effect under different dwelling times and beam currents, and verified by the related experiments. Results show that the local thermal effect of PDMS is very severe for high current density 30 keV Ga+ as its power density spatially can be compressed to 10 9 W / cm 3 . Fabrication experiments on FIB-SEM system are in good agreement with simulations of heat accumulation and thermal evolution of polymer PDMS. This work will improve controllability and precision of FIB fabrication on the flexible sample by considering the incident beam and the sample thermal effect together. [Display omitted] • A practical 3-D power deposition model is built for FIB processing flexible samples. • Model adaptability is improved by studying thermal effect under beam currents. • Model is verified and in good agreement with FIB experiments. • Controllable high-precision fabrication is realized with the new model. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Enhanced weatherability of thermally treated wood surface was achieved by modification of TiO 2 and PDMS. • UV-resistant of TiO 2 treated wood surface was nondurable due to the poor leaching resistance of TiO 2. • The coating of PDMS significantly improved the leaching resistance of TiO 2 nanoparticle due to hydrophobicity of PDMS. Abstract The weathering of thermally treated wood by light radiation and water is an important problem for the wood used in outdoor applications. In this study, a durable hydrophobic and UV-resistant layer was successfully formed on the surface of thermally treated wood at room temperature after in situ deposition of titanium dioxide (TiO 2) nanoparticles and a polydimethysiloxane (PDMS) coating. The morphology of the rutile TiO 2 nanoparticles formed on wood surface, varying from spherical (A-TiO 2) to acicular (B-TiO 2), was tunable by the reaction time between the precursors. Even though the deposited TiO 2 was proved to make the wood surface UV resistant, it was nondurable due to the poor leaching resistance. The successive coating by PDMS significantly improved the leaching resistance of TiO 2 nanoparticles due to the superior hydrophobicity of PDMS. Therefore, the degradation of wood components was reduced, and the removal of chromophoric products in the thermally treated wood was also hindered. [ABSTRACT FROM AUTHOR]

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Highlights • Response rule of cyclic and linear dimethylsiloxanes in FID was preliminarily explored. • An accurate quantitative method for compounds in PDMS 200 fluid was established by GC-FID. • Comparison between the new method and the three traditional methods was conducted. Abstract PDMS 200 fluid (the mixture) was used as standard for quantification of linear dimethylsiloxanes (L5-L16) in environmental matrices. However, the quantification of individual dimethylsiloxane in PDMS 200 fluid by GC-FID was not established or detailed described in many real studies. To solve this problem, we did this research and the principal results were as follows: fifteen compounds in PDMS 200 fluid, including D7, L5 to L16 (12 linear dimethylsiloxanes) and 2 unknown compounds, were identified using GC–MS. Retention indices (RI) of L8 to L16 were first given. Meanwhile, we found that the "effective carbon number (ECN) concept" was applicable for responses of dimethylsiloxanes in FID. Based on GC-FID, a new quantification method for compounds in PDMS 200 fluid was established, detailed described and used to calculate the content of individual dimethylsiloxane in PDMS 200 fluid. Compared with the results from external standard method, internal standard method and normalization method, the new quantification method was more accurate and stable, especially for D7 at low content. [ABSTRACT FROM AUTHOR]

In this study, the effects of halloysite nanotubes (HNTs) reinforcement in expandable graphite based intumescent fire retardant coatings (IFRCs) developed using a polydimethylsiloxane (PDMS)/phenol BA epoxy system were investigated. Intumescent coating formulations were developed by incorporating different weight percentages of HNTs and PDMS in basic intumescent ingredients (ammonium polyphosphate/melamine/boric acid/expandable graphite, APP/MEL/BA/EG). The performance of intumescent formulations was investigated by furnace fire test, Bunsen burner fire test, field emission electron microscopy (FESEM), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and Fourier transform infrared analysis (FTIR). The Bunsen burner fire test results indicated that the fire performance of HNTs and PDMS reinforced intumescent formulation has improved due to the development of silicate network over the char residue. Improved expansion in char residue was also noticed in the formulation, SH(3), due to the minimum decomposition of char carbon. FESEM and TEM results validated the development of silicate network over char layer of coating formulations. A considerable mass loss difference was noticed during thermal gravimetric analysis (TGA) of intumescent coating formulations. Reference formulation, SH(0) with no filler, degraded at 300 °C and lost 50% of its total mass but SH(3), due to synergistic effects between PDMS and HNTs, degraded above 400 °C and showed the maximum thermal stability. XRD analysis showed the development of thermally stable compound mulltie, due to the synergism of HNTs and siloxane during intumescent reactions, which enhanced fire performance. FTIR analysis showed the presence of incorporated siloxane and silicates bonds in char residue, which endorsed the toughness of intumescent char layer produced. Moreover, the synergistic effect of HNTs, PDMS, and other basic intumescent ingredients enhanced the polymer cross-linking in binder system and improved fire resistive performance of coatings. [ABSTRACT FROM AUTHOR]

A technological platform is established for scalable flexible hybrid electronics based on a novel fan-out wafer-level packaging (FOWLP) methodology. Small dielets are embedded in flexible substrates we call FlexTrate. These dielets can be interconnected through high-density wirings formed in wafer-level processing. We demonstrate homogeneous integration of 625 (25 by 25) 1-mm2 Si dielets and heterogeneous integration of GaAs and Si dielets with various thicknesses in a biocompatible polydimethylsiloxane (PDMS). In this paper, 8- $\mu \text{m}$ -pitch die-to-die interconnections are successfully implemented over a stress buffer layer formed on the PDMS. In addition, coplanarity between the PDMS and embedded dielets, die shift concerned in typical die-first FOWLP, and the bendability of the resulting FlexTrate are characterized. [ABSTRACT FROM AUTHOR]

Considerable interest has been motivated in the study of oil-water separation by developing new materials and technologies. Here, we demonstrated a simple and effective method to separate oil-water mixtures using the prepared stainless steel meshes by vapor deposition of liquid state polydimethylsiloxane (PDMS). By changing the heating temperature, underoil superhydrophobic stainless steel meshes and underwater superoleophobic stainless steel meshes can be alternatively achieved. The former is used for heavy oil-water mixtures separation after oil prewetting, while the latter is utilized to separate light oil-water mixtures after water prewetting. As a result, a variety of light or heavy oil-water mixtures could be separated with the efficiency above 99.0%. The separation efficiency maintains high even after 60 separation cycles. In addition, these two types of meshes still take effects under severe environmental situation when they are employed to separate oils from strong acidic, alkaline, salt aqueous solutions, and hot or ice water. [ABSTRACT FROM AUTHOR]

The phase equilibria and saturated fluid properties of CO 2  + PDMS (polydimethylsiloxane) systems were measured to investigate suitability for future hydrodynamic experiments. Two PDMS fluids graded at 100 cSt (M w  = 14 300, M z  = 22 000, Đ M  = 1.59) and 200 cSt (M w  = 18 400,  M z  = 53 000, Đ M  = 4.72) were selected. Saturation pressure, and hence phase transition pressure, was determined for 1–70 wt% PDMS in CO 2 at 313–353 K using the variable volume view cell method (SynVisVar). The density and dynamic viscosity were measured at saturation using the quantified volume and mass, and the converse piezoelectric effect, respectively. In agreement with the literature, the phase equilibria showed complex phase behaviour. Additionally, fluid properties deviated significantly from that of the respective pure components. It was found that both systems exhibited low solubility in CO 2 (<1% above 20 MPa), with properties in the desired ranges (∼900–800 kg/m 3 and ∼0.7–7 mPa.s) for planned future hydrodynamic experiments. [ABSTRACT FROM AUTHOR]

Abstract: Perovskite single crystal (PSC) possesses fewer bulk defects than the polycrystalline film counterpart, which has received extensive attention in a number of optoelectronic device applications. But the management of carrier behavior in an efficient solar cell based on PSC is not reported yet. Here, the carrier behavior within the device based on the ITO/NiOx/(FAPbI3)0.85(MAPbBr3)0.15/TiO2/Ag structure (FA = CH(NH2)2+, MA = CH3NH3+), in which the mixed PSC is successfully implemented into solar cells for the first time, is investigated. The PSC films with lateral dimension from 500 µm to 2 mm and thickness over tens of micrometers, are obtained through the polydimethylsiloxane‐assisted solvent evaporation method. The highest power conversion efficiency derived from the present device approaches 12.18%. It is revealed that the surface roughness and thickness of PSC, the operation temperature and thickness of transport layers, and the interfaces of transport layers/PSC largely impact the carrier extraction and device performance of the perovskite single‐crystal solar cell (PSCSC). This work indicates that the carrier behavior in the absorber layer and transport layer has large impact on the performance of PSCSCs, while the underlying design rule represents an important step to advance the PSCSCs and other optoelectronic devices. [ABSTRACT FROM AUTHOR]

High density gold nanostructures are grown by thermal deposition on flat and nanostructured polymeric templates by exploiting the extraordinarily low wettability of Au on polydimethylsiloxane (PDMS). Undulated PDMS templates are fabricated by replica molding process (REM) on “masters” prepared by defocused Ion Beam Sputtering (IBS). Closely packed and laterally disconnected Au nanostructures are grown at grazing incidence on the PDMS replica templates exploiting the shadowing instability. The peculiar nanocluster morphology determines a Localized Surface Plasmon Resonances (LSPR) which is tunable in the visible range by varying light polarization and metal dose. All samples exhibit a strong increase of the Surface Enhanced Raman Scattering (SERS) intensity with amplification factors exceeding 10 3 . [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane (PDMS) is an important polymer with numerous applications. Herein, the authors report the optical function(s) of PDMS from 191 to 1688 nm as determined from reflection spectroscopic ellipsometry (SE) and transmission ultraviolet-visible data. Two commercial samples of liquid PDMS (PDMS700 and PDMS2000) with molecular weights of 700–1500 g/mol and 2000–3500 g/mol, respectively, were analyzed. Both samples were linear polymers terminated with silanol groups. The optical functions determined from the two materials were essentially identical. Both the reflection and transmission measurements obtained from these materials required special experimental considerations. For the reflection SE measurements, these included roughening (frosting) the inside of the vessel that held PDMS and the need to level the instrument instead of the samples. The transmission measurements were obtained via a dual cuvette approach that eliminated the effects of the cuvettes and their interfaces. In addition to analyzing the data from the individual samples, the SE data from the samples were considered together in a multisample analysis (MSA). Because both samples of PDMS were transparent over the measured wavelength range, and because of the relatively wide wavelength range considered, the optical functions here were fit with Sellmeier models. This produced a good fit for the MSA with a mean squared error value of 1.68. The optical functions obtained in this work agreed well with previously reported values. For example, for the MSA, the authors obtained the following nx values, where x is the wavelength in nanometers: n300 = 1.443, n500 = 1.407, and n1000 = 1.393. [ABSTRACT FROM AUTHOR]

ABSTRACT: In this study, we prepared polydimethylsiloxane (PDMS)‐modified polyurethane–poly(ɛ‐caprolactone) nanofibrous membranes with excellent waterproof, breathable performances via an electrospinning technique. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and mechanical testing were used to characterize the morphologies and properties of the composite nanofibers. The fiber diameter and porous structure of the membranes were regulated by the adjustment of the temperatures of thermal treatment and the PDMS concentrations. The fibrous membranes obtained at a typical temperature of 70 °C possessed an optimized fibrous structure with a diameter of 514 ± 2 nm, a pore size of 0.55–0.65 µm, and a porosity of 77.7%. The resulting nanofibrous membranes modified with 5 wt % PDMS were endowed with good waterproof properties (water contact angle = 141 ± 1°, hydrostatic pressure = 73.6 kPa) and a high breathability (air permeability rate = 6.57 L m−2 s−1, water vapor transmission rate = 9.03 kg m−2 day−1). Meanwhile, the membranes exhibited robust mechanical properties with a high strength (breakage stress = 11.7 MPa) and excellent thermal stability. This suggests that they would be promising candidates for waterproof, breathable applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46360. [ABSTRACT FROM AUTHOR]

This article presents a liquid-metal Galinstan alloy bandpass filter (BPF) with good flexibility, which is fabricated by an improved soft lithography process. The Galinstan alloy is enclosed in the microfluidic channels of elastomeric polydimethylsiloxane (PDMS) substrates. Together with the PDMS substrates, the Galinstan alloy based filter features bending, twisting and stretching capabilities along any direction. A second-order open-loop resonator filter with 2.4 GHz center frequency and 15% fractional bandwidth was designed and fabricated to verify this concept. Experiments show that frequency response of the filter is almost unaffected in the case of bending of the different radii or twisting, while its center frequency slightly shifts down in the stretching condition. The proposed filter can be used for the flexible and conformal electronics. [ABSTRACT FROM AUTHOR]

The effects of ion irradiation on the elastic and surface properties, nanostructure and the chemical changes of the widely used polydimethylsiloxane (PDMS) polymer were investigated as a function of the ion fluence, induced by high-energy ionizing radiation (2.0 MeV proton beam). The polymer was irradiated with different fluences of protons and then the chemical changes, the elastic modulus and surface roughness were investigated by infrared spectroscopy (ATR-FTIR) and Atomic Force Microscopy (AFM). The FT-IR measurements showed very significant chemical changes in the material upon proton irradiation, such as detachment of methyl side groups first, then the starting of the main chain scissions, until the major silicatization of the PDMS by the formation of an inorganic silica like final product (SiO x ). The AFM force curves were obtained by performing contact-mode point-spectroscopy. Their evaluation showed, that the surface elastic properties of PDMS can be controlled in the range of 240 MPa to 49 GPa (Young's modulus) with ion fluencies between 1.68 × 10 13 ions/cm 2 to 1.25 × 10 16 ions/cm 2 , respectively. Compared to the 3–4 MPa of the reference material this indicates a more than four orders of magnitude increase in the elastic modulus of the material. The accompanying changes in the nanostructure of the polymer were characterized with AFM topography measurements and are also discussed in detail. [ABSTRACT FROM AUTHOR]

Toward fabricating a novel multifunctional wound dressing material, we incorporated a series of contents of reduced graphene oxide (rGO) sheets into polydimethylsiloxane (PDMS) matrix to prepare the rGO-PDMS composite membrane and be used for wound dressing. The pore structure, dispersion of rGO, physical properties, water vapor transmission rate (WVTR), cytotoxicity and antibacterial activity were studied. Finally, the effect of the rGO-PDMS composite membrane on wound healing was investigated on a murine full-thickness skin wound model. The rGO-PDMS composite membrane exhibited bionic performance (ordered pore structure and suitable WVTR), improved mechanical properties, good compatibility and effective antibacterial activity. In vivo experiment indicated that the rGO-PDMS composite membrane could accelerate wound healing via enhancement of the re-epithelialization and granulation tissue formation. These findings suggest that rGO doping PDMS uniquely resulted in a multifunctional material for potential use in wound dressing. [ABSTRACT FROM AUTHOR]

Microstructured optical fibers (MOFs) allow a variety of advanced materials to be infiltrated in their air-voids for obtaining the increased fiber functionality, and offering a new versatile platform for developing the compact sensors devices. We aim to investigate the thermal characteristics of high-index core triangular hybrid polymer/silica MOFs with circular air-voids infused with polymer by using the analytical field model [1]. We demonstrate that infiltration of air-voids with polymer, e.g., polydimethylsiloxane (PDMS) can facilitate to tune the fundamental modal properties of MOF such as effective index of the mode, near and the far-field profiles, effective mode area and the numerical aperture over the temperature ranging from 0 °C to 100 °C, for different values of relative air-void ratios. The evolution of the mode shape for a given temperature has been investigated in transition from near-field to far-field regime. We have studied the thermal dependence of splice losses between hybrid MOF and the standard step-index single-mode optical fiber in combination with Fresnel losses. For enhancing the evanescent field interactions, we have evaluated fraction of power associated with fundamental mode of hybrid MOF. We have compared the accuracy of our results with those based on full-vector finite-difference (FD) method, as available in the literature. [ABSTRACT FROM AUTHOR]

Water and oil absorption behaviors of the bare and PDMS (polydimethylsiloxane)-coated PET (polyethylene terephthalate) fabrics with two different fiber strand thicknesses were investigated. PET fabrics were superhydrophobically modified by PDMS-coating via a thermal vapor deposition process. The modification greatly enhanced the selectivity of PET fabric to oil absorption from oil/water mixture, making the PDMS-coated fabric a promising candidate as an absorbent of oil spills. We have also studied oil sorption behaviors of PDMS-coated PET fabric as a function of fiber strand thicknesses and oil viscosities. In general, fabric with a thinner fiber strand thickness showed a higher maximum oil absorption capacity, whereas uptake of the oil in thicker-fiber-absorbent was faster. Based on our results, we suggest that different absorbent structures with various fiber strand thicknesses can be chosen to maximize the efficiency of oil removal, depending on oil viscosity and available oil absorption time. [ABSTRACT FROM AUTHOR]

A versatile and easily customizable mold platform for the microcontact printing of 1D and 2D patterns of dyes is developed. The mold is obtained by optical‐saturable lithography, which is optimized to give a fast process on millimeter size areas. Supported by a kinetic and an electro–magnetic model, 1D and 2D patterns are designed and successfully transferred on the photoresist layer and copied with polydimethylsiloxane (PDMS) to fabricate stamps that are to be used in the printing process. Fluorescence patterning, by means of these PDMS stamp, is validated and compared with the stamp structure. [ABSTRACT FROM AUTHOR]