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Novel polyurethane containing terphenyl groups were designed and synthesized as gate insulators to induce the crystallization of p-sexiphenyl(p-6P) for organic thin-film transistors (OTFTs). Different sizes and shapes of p-6P grains were measured by atomic force microscopy (AFM), and results showed that the large size of p-6P grain can improve the performance of OTFTs. About 900 nm thick films can be easily fabricated by spin-coating under ambient conditions, followed by curing at UV irradiation for 10 min. OTFTs with this film as gate insulator were found to have good processability, a high charge-carrier mobility of 1.1 cm 2 /V s, a threshold voltage of −25 V, and an on/off current ratio >10 5 . The result indicated that this material is a promising candidate for the exploration of devices using OTFTs. [ABSTRACT FROM AUTHOR]

Monodisperse cross-linked polymer microspheres with carboxyl groups on their surface were prepared by means of emulsifier-free emulsion copolymerization. The characterizations by X-ray photoelectron spectroscopy and conductometric titration indicate that most carboxyl groups are located on the surface of microspheres. Their swelling degree or cross-linking degree has been investigated by an in situ swelling method. Moreover, these microspheres can be easily and quickly self-organized into two- or three-dimensional ordered multilayer films or latex crystals. [Copyright &y& Elsevier]

Mobility is an important parameter to estimate the performance of organic thin‐film transistors, one of the key factors affecting the mobility is the first several semiconductors molecular layers near the insulator surface. A strategy is proposed to introduce aromatic‐rings in the gate insulating layer to modulate the growth of pentacene, thus a series of aryl group containing polymers by reversible‐addition‐fragmentation chain‐transfer polymerization is synthesized for the preparation of organic thin‐film transistor insulators. The semiconductor layer is evaporated on the polymer insulators at room temperature. As the inducing function of the aromatic ring, greater weak interactions between dielectric materials and semiconductors by simulation, which makes the initial pentacene layer weak epitaxial growth, therefore pentacene could form better morphology, especially larger crystal domains and uniform thin‐film continuity. The results show that precision design and synthesis of polymer insulator layers provide new methods to achieve high performance of organic thin‐film transistors with easier fabricating process. [ABSTRACT FROM AUTHOR]

Objectives: Outstanding physical-mechanical properties and aging resistance are key requirements for dental resin composite since it will be placed in the oral environment for a long time. In this work, a new dental resin composite mainly modified by glass flakes was fabricated, and the aging resistance was evaluated by comparing with commercial composites without glass flakes. Materials and methods: The new dental resin composite was produced through hand blending of inorganic glass flakes/Si-Al-borosilicate glass (58wt%:7wt% of dental resin composite), POSS-MA (5wt% of resin matrix), Bis-GMA/TEGDMA(64.4wt%:27.6wt% of resin matrix), and CQ/EDMAB (0.9wt%:2.1wt% of resin matrix) together. The flexural strength, elasticity modulus, and hardness, as well as wear were tested for evaluating the aging resistance of different dental resin composite. Results: Among 6 kinds of commercial composites in this study, after 6-month water storage, the maximum percentage of performance degradation is that the flexural strength decreased 39.96%, elasticity modulus decreased 51.53% and hardness decreased 12.52%. In contrast, the new synthesized material decreased 14.53%, 20.88%, and 0.61%, respectively, and performed lesser wear depth compared to some other groups (P < 0.05). Conclusions: It was observed that the new dental resin composite performed better performance stability and wear resistance when compared with commercial dimethacrylate-based or low shrinkage dental resin composite tested in this study. Clinical relevance: This possibly paves a path for designing tailored dental composite for practical application. Since the aging resistance of dental resin composite modified by glass flakes is superior, it has the potential to be used for promoting the durability of dental resin composite. [ABSTRACT FROM AUTHOR]

In order to obtain an ideal material using for artificial corneal skirt, a porous polymer hydrogel containing 2-hydroxyethyl methacrylate (HEMA), trimethylolpropane triacrylate (TMPTA) and butyl acrylate was prepared through one-step radical polymerization method and the usage of CaCO 3 whisker as porogen. The physical-chemical properties of the fabricated polymer hydrogel can be adjusted by CaCO 3 whisker content, such as pore size, porosity, water content of materials and surface topography. Then a series of cell biology experiments of human corneal fibroblasts (HCFs) were carried out to evaluate its properties as an artificial corneal skirt, such as the adhesion of cells on the materials with different pore size and porosity, the apoptosis on materials with different characteristics, the distribution of the cells on the material surface. The results revealed that high porosity not only could improve water content of hydrogel, but also strengthen the adhesion of HCFs on hydrogel. In addition, high porosity hydrogel with the whisker shape of pores showed much elongate spindle-like morphology than those low porosity hydrogels. MTT assay certified that the resulted polymer hydrogel material possessed excellent biocompatibility and was suitable for HCFs growing, making it promising for being developed as artificial corneal skirt. [ABSTRACT FROM AUTHOR]

Urea–formaldehyde resin is widely used as shell materials for microencapsulation of pesticide byin situpolymerization. A series of acetochlor microcapsules were prepared with different formaldehyde to urea molar ratios in this research. Fourier transform infrared spectroscopic analysis suggests that there hardly exists any chemical interactions between shell materials and the acetochlor core materials, and the structure of urea–formaldehyde pre-polymers and shell materials are significantly different when the ratios of formaldehyde to urea increases. The pre-polymer becomes more hydroxymethylated with higher molar ratios, and hydrogen bonds in shell materials interact stronger as well, thus the ratios of formaldehyde to urea affect encapsulation efficiency by hydrogen bonding interactions, which determines the cross-link degree of the shell materials of the prepared microcapsules. [ABSTRACT FROM PUBLISHER]

A series of chromophores based on benzene and thiophene moieties as π-conjugating spacers were designed and synthesized by Horner-Emmons-Wadsworth reaction and Vilsmeier-Haack reaction, followed by Knoevenagel reaction with different electron acceptors. Their structures were confirmed by 1HNMR, FT-IR, HPLC-Ms, UV-visible spectra, and the thermal properties were characterized by differential scanning calorimetry (DSC). Solvatochromic method was used to measure their nonlinear optical properties. The variation of chromophoric structures on NLO properties was investigated, indicating that the cyano substitution on the vinylene bridge of the chromophore produces a considerable red-shift of the absorption maximum, and would greatly enhance the molecular quadratic hyperpolarizability (βμ). [ABSTRACT FROM AUTHOR]

Abstract: A second-order nonlinear thermoplastic epoxy phenolic resin (NLOPF) was synthesized by phenol, p-Nitoaniline, epoxy chloropropane and formaldehyde. The nonlinear optical (NLO) film was fabricated by spin-coating. Then it was poled in the electric field at room temperature. The orientations of the chromophores were fixed by the thermal-cross-linked structures. The second-order nonlinearity of the films was measured by simple reflection technique. The values of electro-optic coefficient (r33) of the films with different chromophore content were 2.32, 4.53, 6.78, 8.65, 10.42pm/V, respectively. They were stabilized around 95% of their initial values after 100h at 80°C. [Copyright &y& Elsevier]

Abstract: A highly stable second-order nonlinear optical multilayer film was constructed on insulating substrates using the electric-field-induced layer-by-layer assembly technique. The substrates used in this method could be arbitrary. In another, the substrates could be modified with polyanion solution by spin coating as cladding layer. Then, the nonlinear optical multilayer films were assembled on the cladding layer directly by the electric-field-induced layer-by-layer assembly technique. The resulting cross-linked multilayer films fabricated by this method displayed high optical transparency, good thermal stability, and excellent nonlinear optical properties which can be made into waveguide devices directly. [Copyright &y& Elsevier]

In this study, polyurethane dimethacrylate (PUDMA) was synthetized from different components and incorporated into a direct resin composite restoration system with the aim to buffer tooth–resin interfacial stresses and maintain the marginal adaptation. The tensile strength, elongation at fracture (ε), and thermal stability of the PUDMA layer were characterized, showing a tensile strength of 22 MPa, an ε of 112%, and a thermal decomposition temperature of about 282°C. In addition, the degree of conversion, water sorption/solubility, hydrophobicity, microtensile bond strength (μTBS), marginal leakage, and cytotoxicity in vitro were evaluated for the PUDMA layer. The data were analyzed using one‐way ANOVA, except for leakage depths (which were analyzed using the Wilcoxon paired‐rank test). The level of significance was set at 0.05. Compared with dental adhesives, PUDMA displayed a higher degree of conversion, lower water sorption/solubility, and improved hydrophobicity and biocompatibility in vitro. After thermocycling, the μTBS of the restoration system containing PUDMA had increased compared with the μTBS at 24 h. Restorations containing PUDMA showed lower leakage depths than those which did not contain PUDMA. In conclusion, because of its hydrophobic and elastic nature, the PUDMA layer, when used as an intermediate between tooth and resin restoratives, may buffer interfacial stresses, improve the stability and durability of the bonding interface, and reduce microleakage. [ABSTRACT FROM AUTHOR]

An interpenetrating polymer network (IPN) structured antibacterial layer was prepared on dental base materials containing quaternary ammonium salt monomers (HMDQAs), polyurethane dimethacrylate oligomers (BIHs) and functionalized SiO2 nanoparticles using a one-step photo-crosslinking method. Scanning electron microscopy (SEM), atomic force microscopy (AFM), ultraviolet near-infrared visible spectrophotometry (UV-3600) and water contact angles were used to study the surface properties of the coatings. SiO2 nanoparticles changed the hydrophilicity of the cationic antimicrobial surface and increased its contact angle. Furthermore, the IPN coatings exhibited highly effective antibacterial activity on the modified dental base material, poly(methyl methacrylate) (PMMA), against Streptococcus mutans, which was evaluated by plate colony counting, optical density (OD), SEM and a live/dead assay. The MTT assay confirmed their biocompatibility. The IPN silicon complexed coating displayed good transparency, excellent antibacterial activity, and no cytotoxicity, which indicated enormous potential for the treatment of denture bases. [ABSTRACT FROM AUTHOR]

Here, we copolymerize a monomer containing naphthyl group with 2-hydroxyethyl methacrylate (HEMA) and glycidyl methacrylate (GlyMA) in various molar ratio to obtain copolymers as functional gate dielectric layers of thin-film transistors (TFTs). Using naphthyl-containing molecule to have similar chemical structure with pentance to adjust the grain size of semiconductor. The results indicated that the semiconductor grains size decreased as molar percentage of naphthyl-containing compound in the polymer structure increased, which could also affect the charge carrier mobility of the pentacene thin-film transistors (TFTs). Therefore, this can be a promising manner to fabricate pentacene TFTs with a high charge carrier mobility by using functionalized dielectric layers to obtain uniform grain size of the pentacene semiconductor. Image 1 • Novel polymer insulating materials containing naphthyl group were designed for OTFTs. • The effect of the content of naphthyl group in the polymers on the mobility was studied. • The larger and more uniformed gain size of pentacene was achieved on the designed polymer surface. • A strategy for the design of polymer as gate dielectric was proposed to improve the mobility of OTFTs. [ABSTRACT FROM AUTHOR]

This paper presents a discussion of the vibration damping enhancement offered by using composites made of partially filled poly(urethane)/polyurea (PU/PUA) microcapsules and E51 epoxy resin (EP). Seven types of microcapsule (with a core mass fraction of about 60 wt%) were prepared in which the core materials were acrylate polymers with different glass transition temperature (Tg, −53.59 °C to 34.40 °C). Dynamic mechanical analysis measurements were performed to investigate the dynamic mechanical properties of the composites, such as storage modulus E′ and loss factor tan δ. The correlations between the dynamic mechanical properties and the Tg of the core material of the partially filled microcapsules were studied. The microcapsule concentration of 15.4 wt% was found to be more efficient in adjusting the tan δ and the Tα of the E51 epoxy. The MP60-4/EP composite reached the highest tan δmax value of 0.82. By controlling the Tg of the core material, the tan δ of composites at the low temperature region increased from 0.12 to 0.29 and the Tα ranged from 77.1 °C to 114.8 °C. [ABSTRACT FROM AUTHOR]

Abstract In this paper, alkyl groups with different lengths are introduced to the two-dimensional spindle-type chromophores as the steric isolators to improve the poling efficiency and long term stability of the poled polymers for second-order nonlinear optical materials. The structure and thermal properties of alkyl functionalized chromophores are characterized by the 1H NMR, FT-IR, UV–Vis, DSC, TGA et al. The chromophores with different alkyl groups present extremely similar maximum absorbance wavelength (480 nm), which means they have very similar first-order hyperpolarizability. Guest-host polymer doped with chromophores has been prepared. Those materials display different glass transition temperatures and good thermal stability. According to the electro-optic coefficients studies and poling efficiency results, chromophores with longer alkyl side chain groups exhibit better poling efficiency and larger electro-optic coefficients. Especially for the chromophores with octyl group, the poling efficiency increases up to 3 times compared to the reference chromophore 2-(3-{2,5-Phenylmethanol-4-[4-(dimethylamino)styryl]-styryl-5,5-dimethylcyclohex-2-enylidene)malononitrile (STC), while the corresponding electro-optic coefficient of the poled polymers increases up to 4 times, indicating a significant effect of the isolate groups on improving the poling efficiency. Highlights • We synthesized a series of two-dimensional spindle-like chromophores with different length of alkyl groups. • Two-dimensional spindle-like chromophores had good thermal stabilities and met the requirements of the poling process. • Chromophores with longer alkyl groups and linear alkyl group had better long-term stability, poling efficiency and larger electro-optic coefficient. • Poling efficiency of chromophores with octyl group increased up to 3 times and electro-optic coefficient of poled polymers increased up to 4 times compared to STC. [ABSTRACT FROM AUTHOR]

Liquid viscoelastic polymers are promising materials for vibration damping due to their superior damping properties. However, using liquid polymers as materials for this purpose is challenging because liquid polymers cannot be used as normal materials in their amorphous fluid state. This study reports polyurethane/polyurea (PU/PUA) microcapsules prepared using oil-in-water (O/W) emulsion and interfacial polymerization. The microcapsules were partially filled with silicone oil and used as a damping filler in an epoxy resin specimen. Dynamic mechanical analysis measurements (DMA) were performed to investigate the loss factor tan δ of the epoxy resin blended with the microcapsules. The DMA results indicated that the partially filled structure of the microcapsules could enhance the vibration absorbing property of the epoxy resin specimen, and the maximum loss factor (tan δ) increased from 0.38 to 0.79. The loss factor of the epoxy resin could be controlled by the core volume fraction and the concentration of the microcapsules in the epoxy resin. [ABSTRACT FROM AUTHOR]

In this study, we design and synthesize a novel photosensitive polyurethane material as a functional dielectric layer, which can adjust the crystallization of para-hexaphenyl (p-6P). The novel polymer is synthesized with a new monomer 2,2-bis(hydroxymethyl)butyl 4-cyanobenzoate (HM-4-CB), which contains benzene to provide crystal nucleus sites. The grain size and density of the p-6P crystal can be controlled by the content of HM-4-CB in the polymer structure. Therefore, this method can be used to regulate the grain size of semiconductor crystals and then to change the carrier mobility of the device. The results illustrate that with a suitable grain size of the p-6P semiconductor, excellent performance in terms of charge carrier mobility can be obtained. [ABSTRACT FROM AUTHOR]

Superhydrophobic coatings were successfully fabricated by photo-crosslinked polyurethane (PU) and organic fluoro group-functionalized SiO 2 nanoparticles (F-SiO 2 NPs), and were introduced for preventing microleakage in a dental composite restoration. The F-SiO 2 NPs possessed low surface energy and the PU can not only improve the mechanical stability but also promote F-SiO 2 NPs to form multiscale structure, which could facilitate the properties of the as-prepared superhydrophobic coating by synergetic effect. The morphology and properties of the resulted superhydrophobic coatings with different PU/F-SiO 2 ratios were studied using 1 H NMR spectrum, fourier transform infrared spectra, scanning electron microscopy, atomic force microscopy and UV–vis spectrophotometry. The results showed that the superhydrophobic coatings with low PU/F-SiO 2 ratio (1:3) possessed excellent hierarchical papillae structure with trapped air pockets, high contact angle (160.1°), low sliding angle (< 1°) and good transparency. Additionally, MTT experiments results certified the prominent cell viability and biocompatibility for clinical application. Based on its fantastically superhydrophobic property, the as-prepared superhydrophobic coatings effectively prevented water permeation in resin composite restoration evaluation. This research may provide an effective method to solve the problem of microleakage and will efficiently increase the success rate of dental composite restorations. [ABSTRACT FROM AUTHOR]

A kind of fluorinated and epoxy-terminated low-molecular-weight bisphenol A polycarbonate (FBPA-PC EP) was synthesized by solution polymerization of 4, 4′-(hexafluoro-isopropylidene) diphenol (6F-BPA) with triphosgene (BTC) and further reacted with epoxy chloropropane. The structure of the polymer was confirmed by FTIR, 1 H NMR, 13 C NMR and 19 F NMR spectra. A series of negative-type fluorinated photoresists (NTFPs) were prepared by mixing of FBPA-PC EP and FSU-8 with triphenylsulfonium hexafluorophosphate and cyclopentanone as the photoacid generator (PAG) and solvent. The polymer films prepared from NTFPs by UV-curing exhibited superior chemical resistance, excellent thermal stability (Tds ranged from 295 to 303 °C) and low surface roughness. A clear negative pattern was obtained through direct UV photo-cross-linking and then chemical development which can be used as high-quality channel waveguides (the roughness of the lateral ridge ranged from 21 to 32 nm (1 × 1 μm)). For waveguides with the polymethylmethacrylate as upper cladding, the propagation loss of the channel waveguides was measured to be 0.25 dB/cm at the monitoring light of 1550 nm. [ABSTRACT FROM AUTHOR]

Lanthanide-doped luminescent nanoscale materials have great potential applications in biological researches. Herein, we reported a novel and mild method for one-step synthesis of chitosan/4:3+ nanocomposites. The luminescent 3+ ions and magnetic resonance imaging (MRI) contrast agent 3+ ions were incorporated to these biocompatible nanocomposites. The resultant nanocomposites exhibited strong fluorescence and attractive magnetic features. The nanocomposites also have pure hexagonal phase with uniform size of about 65 nm. FT-IR spectra revealed that these nanocomposites were successfully coated by hydrophilic chitosan, whose amine groups conferred the nanocomposites excellent dispensability in aqueous solution. Besides, the MTT assay and laser confocal microscopy images have confirmed the good biocompatibility of the nanocomposites. These results indicated that the as-prepared nanocomposites could be used as an excellent targeted imaging agent in biological fields. Lanthanide-doped luminescent nanoscale materials have great potential applications in biological researches. Here, a chitosan/ NaGdF4:Eu3+ nanocomposites have been fabricated by a novel and mild one-step synthesis method. Biocompatible chitosan is used to induce the growth of NaGdF4:Eu3+ NPs and stabilize the NPs against the formation of unexpected aggregation. The resultant nanocomposites with uniform size of about 65 nm exhibited strong fluorescence and magnetic features with excellent biocompatibility. [ABSTRACT FROM AUTHOR]

Abstract: A research on the design, synthesis, and characterization of novel cross-linked polymer organic–inorganic hybrid materials as gate insulators for organic thin-film transistors (OTFTs) with vanadyl-phthalocyanine as the organic semiconductor is presented. The hybrid films (0.5–1.2μm thick) can be easily prepared by sol–gel technology and fabricated by spin-coating a mixture of zirconium n-butoxide sol with a side-chain triethoxysilane-capped polyurethane solution in ambient conditions, followed by curing at low temperatures (∼120°C) and cross-linking under UV light. OTFTs with this film as gate insulator were achieved with good processability, high charge-carrier mobility of 0.56cm2/Vs, surface roughness of around 0.49–0.59nm, ultralow threshold of −6V, and ultralow leakage of 0.24mA. Hybrid films with various compositions were investigated, and the results showed that the field-effect mobility of the OTFTs was dominated by the high dielectric constant component ZrO2. The result indicated that these hybrid materials are promising candidates for the exploration of devices using OTFTs. [Copyright &y& Elsevier]

Abstract: A series of two-dimensional spindle-type chromophores has been synthesized. The detailed synthetic procedure was reported. The factors that influence the nonlinear optical properties such as the donors and acceptor character have been investigated. The chemical structures of the target products have been confirmed by IR, UV–Vis and NMR spectroscopy, elemental and thermal analysis. The spindle-type chromophores have been used to prepare host-guest doped films which exhibited very good thermal and temporal stability. The nonlinear electro-optical coefficients of the host-guest doped films were measured by the Teng-Man technique and gave values in the range from 21 to 29 pm/V. [Copyright &y& Elsevier]

Abstract: A bisphenol monomer (4-methoxy) phenylhydroquinone (Me-HQ) was prepared and further polymerized with 2,2,3,3,4,4,5,5,6,6,7,7-dodeca-fluoro-1,8-octanediol (12F-diol) and decafluorobiphenyl (DFBP) to obtain highly fluorinated aromatic-aliphatic copolyethers containing methoxy groups. After demethylation and the reaction with epoxy chloropropane, a series of novel highly fluorinated aromatic-aliphatic copolyethers bearing epoxy groups (FA-APE EP) at different feed ratios of (Me-HQ)/(12F-diol) were obtained. The chemical structures of all the copolymers were analyzed by 1H NMR, 13C NMR and 19F NMR spectra. A series of highly fluorinated photoresists were prepared by composing of fluorinated copolyethers, diphenyliodonium salt as a photoacid generator (PAG) and solvent. After UV-curing, the cross-linked films exhibited excellent chemical resistance and high thermal stability (Td ranged from 230 to 278 °C). The refractive indices of the films could be controlled between 1.5127 and 1.4749 at 1550 nm by varying the feed ratio of comonomers. A clear negative pattern was obtained through direct UV exposure and chemical development. For waveguides without upper cladding, the propagation loss of the channel waveguides was measured to be 0.18 dB/cm at 1550 nm. [Copyright &y& Elsevier]

Abstract: Two novel two-dimensional spindle-type fluorinated chromophores with fluorinated phenyl as side groups connecting to the π conjugated bridge were prepared for second-order nonlinear optical applications. The detailed synthetic procedure was reported. Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed that the spindle-type fluorinated chromophores have excellent thermal stability. Host–guest doped materials had been used to prepare the second-order nonlinear optical films. The nonlinear electro-optic (EO) coefficient of the poled films was measured by Teng–Man technique at the fundamental wavelength of 1310nm, and the r 33 up to 28pm/V was achieved. [Copyright &y& Elsevier]

In this paper, a new type of single-mode embedded dye-doped electro-optic (EO) polymeric waveguide switch based on cross-linkable negative photoresist was successfully designed and fabricated using direct photodefinition technique. The optical properties of the UV cross-linkable poled polymer were characterized. By optimizing the poling temperature and the dopant levels of Disperse Red 1, the DR1/SU-8 material showed excellent photostability and exhibited an EO coefficient, \gamma33, of 25 pm/V. The characteristic parameters of both the waveguide and the electrode were carefully designed and simulated by MATLAB program. The Mach–Zehnder interferometer switch on-off time obtained was about 6 \mus. The new fabrication technique is a simple, rapid, and controllable process. The easy-to-fabricate waveguide structure is suitable for planar active lightwave circuit applications. The dye-doped polymer photosensitive waveguide devices will be very useful in realizing EO modulators and switches. [ABSTRACT FROM AUTHOR]

Abstract: A series of novel spindle-like terphenyl-type chromophores, based on 2,5-diphenyl-1,4-distyrylbenzene π-conjugating bridge, N,N-dimethyl and triphenyl amino donors, and Tricyanovinyldihydrofuran(TCF), 1,3,3-trimethyl-5-dicyanovinyl-1-cyclohexene (TDC) acceptors, have been synthesized successfully for the first time. And the non-linear optical properties were evaluated by using the finite-field (FF) method. The results show that, the first-order hyperpolarizability of the chromophores increase with the increase of the withdraw ability of the substituent group on the π-conjugating bridge. [Copyright &y& Elsevier]

A series of highly fluorinated polymers were synthesized by copolymerization of 2,3,4,5,6-pentafluorostyrene (PFS) and fluorinated styrene derivate monomer (FSDM). Their chemical structure were confirmed by 1H NMR, 13C NMR, and 19F NMR spectra. The refractive index and cross-linking density of the polymers can be tuned and controlled by monitoring the feed ratio of comonomers. A series of negative-type low-molecular-weight fluorinated photoresists (NFPs) were prepared by composing of fluorinated polystyrene derivates (FPSDs), diphenyl iodonium salt as a photoacid generator (PAG) and solvent. The polymer films prepared from NFP by photocuring exhibited excellent chemical resistance and thermal stabilities ( Td ranged from 230.5 to 258.1 °C). A clear negative pattern was obtained through direct UV exposure and chemical development. For waveguides without upper cladding, the propagation loss of the channel waveguides was measured to be 0.25 dB/cm at 1550 nm. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 [ABSTRACT FROM AUTHOR]

Abstract: This work focused on the development of a novel method for molecular level assembly and processing of inorganic–organic hybrid second-order nonlinear optical (SONLO) multilayer films. Aromatic diazo group linked silicon sol was first synthesized and used as a polycation. This oligomer was assembled into inorganic–organic hybrid SONLO multilayer films by electric-field-induced layer-by-layer assembly technique with a low molecular weight chromophore molecule as an anion. After UV irradiation, the electrostatic interaction between layers converted to covalent bonds. Large second-harmonic generation signal of the assembled film was observed, which confirmed that the chromophore in the film had a high degree of molecular orientation as assembled under the electric field. As the cross-linked structure and silicon oxygen meshwork in the films, the resulting inorganic–organic hybrid multilayer films displayed good thermal and chemical stability, and excellent NLO properties. [Copyright &y& Elsevier]

A novel method for the preparation of thin films of Ag nanoparticles is reported. Using mercaptoacetic acid as the stabilizing agent, AgI nanoparticles were prepared in aqueous solution. And based on electrostatic interactions, the thiol-passivated AgI nanoparticles were assembled in a self-assembled film by alternative deposition with a cationic polyelectrolyte. Then the AgI nanoparticles in the composite film were reduced by NaBH4, which resulted in the formation of a thin film of Ag nanoparticles. UV-visible spectra and X-ray photoelectron spectroscopy data confirmed the transformation from AgI to Ag. Atomic force microscopy (AFM) showed that the formed Ag nanoparticles distributed on the film homogeneously. Surface-enhanced Raman spectroscopy (SERS) measurement indicated that the prepared thin films could be used as effective SERS substrates. The reduction process was also carried out by UV light at selective surface regions, which resulted in the formation of patterned nanoparticle arrays. [Copyright &y& Elsevier]

Abstract: In this work, hollow mesoporous aluminosilica spheres were prepared by alkaline etching method and loaded with silver chloride (AgCl) to act as antibacterial agent. The hollow mesoporous aluminosilica spheres possess radially oriented ordered mesopore channels and a high loading amount of AgCl. Then, the AgCl loaded hollow mesoporous aluminosilica spheres were doped in a polymer coating with different weight ratio to fabricate antibacterial coatings. The antibacterial activity of the coatings was tested against the fungus Candida albicans (ATCC 10231) which usually causes denture stomatitis. The hardness and adhesion of the coatings were also tested. The results showed that the coatings exhibited high antibacterial activity, high hardness and good adhesion to the substrate, and showed a great potential in the application in PMMA based denture materials. [Copyright &y& Elsevier]

Abstract: In this paper, functionalized alkoxysilane dye (ICTES-STC) was formed by the reaction of two-dimensional spindle-type chromophores (STC) with 3-isocyanatopropyltriethoxysilane (ICTES). The transparent films having silica network matrix and covalently bonded chromophores were fabricated via the sol–gel process. From TGA thermogram, the initial decomposition temperature of the hybrid film was determined to be 269°C. The electro-optic (EO) coefficient (r33) of the poled films was measured to be around 12pm/V by Teng–Man technique. The thermal stability of the NLO coefficient of the film was investigated by the depoling experiment and temporal decay test, and the result showed that the hybrid film had a good thermal stability, implying its potential applications for EO devices. [Copyright &y& Elsevier]

Abstract: The Er3+–Yb3+ codoped silica/titania core–shell nanoparticles were prepared by hydrolysis of titanium alkoxide precursors in the presence of lanthanide ions via sol–gel method. The structure of the particles was characterized by field emission scanning electron microscopy and transmission electron microscopy. The diameter of the silica core is about 50nm. The thickness of the titania shell is about 4nm. A typical doping density of Er3+ in the titania shell is 4.51at.%, and the one of Yb3+ is 12.20at.%. The UV–vis–NIR absorption spectra and the photoluminescence spectra were also investigated. [Copyright &y& Elsevier]

Abstract: A photo-cross-linked stable organic–inorganic hybrid second-order nonlinear optical (NLO) film was fabricated by sol–gel process with silicon sol linking aromatic diazonium group (SOD) and Chromophore molecule 2-({4-[4-(2-carboxy-2-cyano-vinyl)-phenylazo]-phenyl}-methyl-amino)-ethyl acid (DRCB). The films were poled under 50DC voltage electric field at room temperature at the existence of solvents. After the solvents volatilized completely and upon UV irradiation under the electric field, the ionic bonds converted to stable covalent bonds in the system, the orientations of the chromophores were fixed by the photo-cross-linked structures. The order parameter of the fabricated film can retain 99% after 17days at room temperature. The stable organic–inorganic hybrid photo-cross-linked NLO films fabricated in this paper had large potential to be applied in electric-optic devices. [Copyright &y& Elsevier]

A series of fluorinated polycarbonates (AF-3OH-PC MAs) terminated by different proportions of acrylate group were synthesized and directly used as photoresist materials. The materials can directly form a cross-linked film under UV light and initiator conditions without the addition of small molecular crosslinkers. The thermal stability (Td up to 416 °C), the absorption at 1550 nm is almost zero and electro-optical stabilities (after 80 °C for 200 h, the r 33 remains 91% of the initial value) are significantly improved since the small molecular crosslinkers were not added. The propagation and insertion loss of the device were measured by a cut-back method to be only 0.66 dB/cm and 1 dB, respectively. It may be possible to have an enlightening effect on preparing electro-optical switches with better performance. Image 1 • The photoresist can be crosslinked by UV light in the presence of a chromophore. • The film also have a smooth surface, and controllable refractive indices (n = 1.495–1.533). • The photo-crosslinked films owned excellent thermal stability (T g1 = 147 °C, T d1 = 416 °C). • The electro-optical stability (r 33 remains 91% after 80 °C for 200 h) and the optical loss (0.66 dB/cm) are improved. [ABSTRACT FROM AUTHOR]