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The lower critical solution temperature (LCST) behaviour of block copolymer 2-(2-methoxyethoxy) ethyl methacrylate and oligo (ethylene glycol) methacrylate (P(MEO2MA-b-OEGMA)) was studied by molecu...

In this work, a novel redox hydrogel was proposed for ultrasensitive label-free electrochemical detection of a carcinoembryonic antigen (CEA). The redox hydrogel composed of cellulose nanocrystals (CNCs), methylene blue (MB), multi-walled carbon nanotubes (MWCNTs), and polydopamine-reduced graphene oxide-gold nanoparticles (PDA–rGO–AuNPs) was formed by electrostatic and hydrophobic interactions among these components. The larger surface to volume ratio, outstanding hydrophilicity, excellent film-forming ability and the gelatinization of CNCs provided the premise for the formation of a gel with excellent properties including larger specific surface area (101.05 m2 g−1), better adhesive ability to glassy carbon electrodes (GCEs), etc. The addition of MWCNTs to hydrogel could improve the adsorption of redox MB. The synthesized PDA–rGO–AuNPs gel was integrated into a hydrogel not only for improving the conductivity but also for providing more sites for immobilization of antibodies. The obtained CNC–MB–MWCNT–PDA–rGO–AuNPs gel was then applied to modify GCE and the gel/GCE demonstrated higher stability and exhibited a strong redox performance (current signal appeared at −0.156 V (vs. Ag/AgCl)). The immunoassay platform was constructed after the gel/GCE was incubated with anti-CEA and blocked by bovine serum albumin (BSA) in succession. The proposed immunosensor exhibited a wider linear range from 1 fg mL−1 to 200 ng mL−1 with an ultralow detection limit of 0.011 fg mL−1 (at a signal to noise ratio of 3). Furthermore, the immunosensor demonstrated higher selectivity, excellent reproducibility, remarkable stability, and better reliability for real sample analysis, which implied a promising potential for the determination of CEA in clinical application.

Photoresponsive systems with controllable self-assembly morphologies and adjustable rheological properties have attracted widespread interest by researchers in the past few years. Among them, the p...

In this work, the chromogenic catalysis of 3,3’,5,5’-tetramethylbenzidine (TMB) with horseradish peroxidase (HRP) in presence of hydrogen peroxide (H2O2), the most widely used chromogenic reaction ...

Azobenzene is one of the most commonly used photoresponsive molecules due to its light induced trans/cis transition, and it is widely used in many fields such as drug delivery. In this paper, we us...

Pulmonary administration is widely used for the treatment of lung diseases. The interaction between drug molecules and pulmonary surfactants affects the efficacy of the drug directly. The location and distribution of drug molecules in a model pulmonary surfactant monolayer under different surface pressures can provide vivid information on the interaction between drug molecules and pulmonary surfactants during the pulmonary administration. Ketoprofen is a nonsteroidal anti-inflammatory drug for pulmonary administration. The effect of ketoprofen molecules on the lipid monolayer containing 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-glycerol (DPPG) is studied by surface pressure (π)-area (A) isotherms and compressibility modulus (Cs-1)-surface pressure (π) isotherms. The location and distribution of ketoprofen molecules in a lipid monolayer under different surface pressures are explored by surface tension, density profile, radial distribution function (RDF), and the potential of mean force (PMF) simulated by molecular dynamics (MD) simulation. The introduction of ketoprofen molecules affects the properties of DPPC/DPPG monolayers and the location and distribution of ketoprofen molecules in monolayers with various surface pressures. The existence of ketoprofen molecules hinders the formation of liquid-condensed (LC) films and decreases the compressibility of DPPC/DPPG monolayers. The location and distribution of ketoprofen molecules in the lipid monolayer are affected by cation-π interaction between the choline group of lipids and the benzene ring of ketoprofen, the steric hindrance of the lipid head groups, and the hydrophobicity of ketoprofen molecule itself, comprehensively. The contact state of lipid head group with water is determined by surface pressure, which affects the interaction between drug molecules and lipids and further dominates the location and distribution of ketoprofen in the lipid monolayer. This work confirms that ketoprofen molecules can affect the property and the inner structure of DPPC/DPPG monolayers during breathing. Furthermore, the results obtained using a mixed monolayer containing two major pulmonary surfactants DPPC/DPPG and ketoprofen molecules will be helpful for the in-depth understanding of the mechanism of inhaled administration therapy.

A new lubricating coating with functionalized graphene oxide (fGO) consisting of graphene oxide (GO) with different oxidation degrees, n-octylamine basal plane functionalized GO (bGO), and edge functionalized GO (eGO) was developed with or without 3-aminopropyltrimethoxysilane (APTMS) to reduce friction in macroscale contact with water. The optimal preparation condition of the coating was obtained by the single factor evaluation of a series of factors (20 % APTMS aqueous solution, 12 h immersion time, 0.05 mg/mL GO aqueous solution, and 100 °C curing temperature). The effect of the oxidation degree and functionalization of GO on the friction-reducing and anti-wear behavior of the coating was explored. The coatings with a higher GO oxidation degree exhibited better friction-reduction and anti-wear performance. In addition, the friction-reducing capability of the APTMS-bGO coating was greater than that of APTMS-eGO.

The photoresponsive wormlike micelles constructed by Gemini surfactants and cinnamate derivatives play a great role in the field of smart materials. However, how the structure of cinnamate derivatives affects the photoresponsive behavior of micelles is still a hotspot for scientists to research. Here, three kinds of aromatic salts with different ortho-substituted groups including trans- o-methoxy cinnamate ( trans-OMCA), trans- o-hydroxy cinnamate ( trans-OHCA), and trans-cinnamate ( trans-CA) were introduced into Gemini surfactant 12-3-12·2Br- aqueous solutions to construct photoresponsive wormlike micelles through their noncovalent interactions. Their properties were researched using the rheological method, cryo-transmission electron microscopy, and 1H NMR and two-dimensional nuclear Overhauser effect spectra. The results show that these cinnamate derivatives could well construct wormlike micelles with 12-3-12·2Br-. Furthermore, subtle differences in the ortho substituents' structure have a significant effect on the photoresponsive behavior of formed wormlike micelles. Specifically, the zero viscosity (η0) of 40 mM 12-3-12·2Br-/24 mM trans-OHCA mixed solution decreases from 26.72 to 2.6 Pa·s with the shortening of the length of wormlike micelles after UV irradiation. Correspondingly, the η0 for the same ratio of 12-3-12·2Br-/ trans-OMCA decreases from 2.42 to 0.06 Pa·s and the wormlike micelles are transited into rodlike micelles and even spherical micelles after the same UV irradiation time. However, the variation of wormlike micelles in the 12-3-12·2Br-/ trans-CA system induced by UV light is not obvious with η0 being maintained at around 2.89 Pa·s. This study will help us better understand the effects of chemical groups on macrophenomena and microinteraction for micellar systems. It provides a theoretical basis for the construction of photoresponsive micelles, thus widening their application in the field of soft materials.

In this work, four types of comb-like dispersants and one linear dispersant were synthesized to explore the effect of dispersant structure on the bubble structure in water solution and mortar system for the first time. Dispersants were modified with different adsorption groups (i.e., carboxylic acid, phosphate ester, and sulfonic groups). Polymer structures were identified using gel permeation chromatography and infrared spectroscopy. Surface tension test indicated that the comb-like dispersants exhibited lower surface tension than that of the linear dispersants (NSF-2), thereby demonstrating that the polycarboxylate superplasticizer (PCE) solutions possessed high surface activity. The analysis of the foamability and foam stability of the comb-like and linear dispersants were comprehensively investigated at different concentrations. Comb-like dispersants possessed higher foam height and better foamability performance than those of the linear dispersants. The bubbles of the dispersant PCE-3 were smaller in terms of the mean area and possessed higher number of bubbles than those of the other dispersants, which may be essential in reducing the viscosity of the slurry. A similar result was also obtained in the mortar system tested using the AVA instrument for PCE-3 and NSF-2. Adsorption and rheological behavior test indicated that comb-like dispersant PCE-3 is the most effective in reducing the viscosity of the slurry among all the dispersants tested. This result is consistent with that of the foamability experiment.

Mixed surfactants have potential applications in various fields. The understanding and prediction of their macro- and microscopic properties are of great importance in the designing of these materi...

Photoresponsive systems with adjustable self-assembly morphologies and tunable rheological properties have aroused widespread concern of researchers in recent years because of their prospect applications in controlled release, microfluidics, sensors, and so forth. In this paper, we combine a cationic Gemini surfactant 12-3-12·2Br– and trans-2-methoxy-cinnamate (trans-OMCA) together to create a representative UV-responsive self-assembly system. The system displays abundant self-assembly behaviors, and the self-assemblies with different states and different scales including wormlike micelles, vesicles, and lyotropic liquid crystals (LCs) as well as an aqueous two-phase system (ATPS) are observed even at lower surfactant concentration. The UV-responsive behavior of the formed self-assemblies is investigated systematically. The results have shown that the photoisomerization of OMCA from trans form to cis form under UV light irradiation alters the hydrophobicity and steric hindrance effect of OMCA and thus aff...

The interaction between star-shaped copolymer poly(2-(dimethylamino)ethyl methacrylate-b-2-(2-methoxyethoxy)ethyl methacrylate) (CDPDPM) and anionic surfactant sodium dodecyl sulfate (SDS) in aqueous solutions are investigated by using fluorescence and dynamic light scattering (DLS) techniques. The effects of nonionic surfactant dodecyl β-D-maltopyranoside (C12G2) and salts including inorganic salt ammonium bromide (NH4Br) and organic salt tetra-n-butylammonium bromide (Bu4NBr) on the interaction between CDPDPM and SDS have been explored systematically. The results have suggested that SDS molecules can bind on CDPDPM by electrostatic interaction between the positively charged CDPDPM and negatively charged SDS and thus weaken the binding ability of CDPDPM to water molecules. CDPDPM exhibits temperature-responsive aggregation behavior in aqueous solution gradually with the increase of SDS concentration and the lower critical solution temperature (LCST) decreases correspondingly. The introduction of nonionic surfactant C12G2 changes the interaction between CDPDPM and SDS significantly by participate the formation of complexes and the stability of the CDPDPM/SDS complexes declines leading to the chance of forming larger complexes is deprived at higher temperature. The addition of NH4Br to the CDPDPM/SDS system can retard the binding of SDS on the polymer chains because of electrostatic shielding. Correspondingly, LCST is higher and the formed aggregates are smaller. For CDPDPM/Bu4NBr/SDS system, the phenomenon is similar to that of the CDPDPM/C12G2/SDS system. This should be attributed to the nature of Bu4N+, possesses not only positive charges but also certain hydrophobicity, and thus Bu4N+ has the ability to participate and facilitate the formation of SDS micelles. Obviously, the LCST of the mixed system can be tailored by adjusting the system composition on purpose.

The gelation behavior and properties of sodium deoxycholate (NaDC) and L-aspartic acid (Asp) in aqueous solution were investigated in detail at 25 °C. The linear polymer poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo-(ethylene glycol) methacrylate) (P(MEO2MA90-co-OEGMA10)) and star-shaped polymer poly(2-(dimethylamino)ethyl methacrylate-b-2-(2-methoxyethoxy)ethyl methacrylate) (CDPDPM) were introduced in NaDC/Asp hydrogels for exploring the effects of polymers on the properties of NaDC/Asp hydrogels and the mechanism underlying gelation processes by polymers was proposed. The hydrogels were characterized by phase behavior observation, polarized optical microscopy (POM), cryogenic scanning electron microscopy (cryo-SEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and rheological measurements. Moreover, the adsorption performances of hydrogels with and without polymers to methylene blue (MB) were studied using a UV-vis spectrometer. The results indicated that the transition from sol to gel state was observed with an increase in the Asp concentration in the system. Both linear and star-shaped polymers can participate in the formation of a gel network structure, so that the density of network structure and the mechanical strength of hydrogels increased. Furthermore, it was found that the viscoelasticity of the CDPDPM-containing hydrogel was much higher than that of the P(MEO2MA90-co-OEGMA10)-containing hydrogel under the same condition, indicating that CDPDPM performed better in strengthening the network structure of the hydrogels than P(MEO2MA90-co-OEGMA10) due to the special structure that provided more binding sites for hydrogen bonding and stronger hydrophobicity that inhibited the swelling and dissolution of hydrogels. On coming in contact with the MB solution, the CDPDPM-containing hydrogel can adsorb MB and maintain the hydrogel state for recycling. On the contrary, the NaDC/Asp hydrogel dissolved and P(MEO2MA90-co-OEGMA10)-containing hydrogel collapsed in the MB solution. The properties of the hydrogels are expected to be tailored by introducing polymers with different properties, including the charge numbers, the number of available binding sites, and hydrophobic properties.

MoS2 coating is an effective way to suppress the growth of lithium dendrites, but the study of the layer spacing effect is still lacking. In this work, the diffusion and adsorption of lithium ions on the MoS2 were studied by multiscale simulations. The transport of lithium ions on the MoS2 was investigated by a continuum method, which shows that the smaller layer spacing of 1 nm can enhance the ion diffusion. The QDFT method was used to study the lithium ions transport on 1T- and 2H- MoS2 with layer spacing of 0.65 nm - 1.15 nm. Results indicate that lithium dendrites are more difficult to grow on 2H- MoS2. For both types of MoS2, enlarged layer spacing can reduce lithium dendrites growth and 0.75 nm is the most suitable interlayer distance for MoS2 expanding. We hope our results can provide guidance to the synthesis of dendrite-free lithium metal batteries.

A series of star-shaped block copolymers (CDPDPM) of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) with tunable stimuli-responsive behavior are synthesized via sequential atom transfer radical polymerization (ATRP) with the 2-bromoisobutyryl-terminated β-cyclodextrin (β-CD) as a core. The properties of these star-shaped copolymers are characterized by FT-IR, NMR and GPC analyses. Meanwhile, the thermo-sensitive behaviors of CDPDPM with different compositions and pH values are investigated by dynamic light scattering (DLS) and UV–vis measurements. The results have shown that the synthesized polymer CDPDPM exhibits both pH- and thermo-responsive behaviors in aqueous solutions. The star-shaped copolymers with the nearly equal mole fraction of DMAEMA and MEO2MA show two-step thermo-induced aggregation behavior in water at a pH near the isoelectric point (IEP), which corresponds to the formation of branch aggregates and large aggregates consisting of clustered branch aggregates, respectively. The mole fraction of DMAEMA and MEO2MA in polymer affects the thermal-responsive behaviors of polymer itself. Moreover, the micellar behaviors of the synthesized copolymers in aqueous solution are explored. The aggregation process of the copolymer can be generalized into intramolecular aggregation of the hydrophobic chains (corresponding to CI), formation of premicelles, the aggregation and rearrangement of the premicelles (namely CMC), as well as the formation of multicore structures. The CI and CMC values depend on both the MEO2MA molar fraction and the carbon backbone length of polymers. The aggregation number (N) and the sizes of polymer micelles (Dh) vary with the polymer composition, polymer concentration and ambient environment.

The traditional surfactant sodium dodecyl sulfate (SDS) and ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF 4 ]) have been combined to create a novel efficient medium for chromogenic catalysis of 3,3′,5,5′-tetramethylbenzidine with horseradish peroxidase in presence of H 2 O 2 . The results have shown the [Emim][BF 4 ] in the mediums can promote the rate of formation of the blue chromogen, the SDS is responsible for the stabilization of the blue chromogen due to the electrostatic attraction between positively charged blue chromogen and the negatively charged surfactant. The SDS/[Emim][BF 4 ] combination not only enhance catalytic activity of HRP remarkably but also stabilize the blue chromogen formed in the HRP oxidation of the substrate TMB compared to the conventional medium. Based on the superior combination of SDS and [Emim][BF 4 ], the colorimetric assay for detecting HRP activity and H 2 O 2 concentration was established. This work demonstrates a novel efficient medium for chromogenic catalysis with potential applications in biosensors and clinical diagnosis.

The authors describe biocompatible nanomicelle based drug carriers that can be used for simultaneous (a) fluorescence tracking, (b) pH-controlled release of the cancer drug doxorubicin (DOX), and (c) targeting the folate receptor. The pH-sensitive triblock copolymer is composed of poly-2-(diisopropylamino) ethyl methacrylate and methoxypoly (ethylene glycol) which were prepared by radical polymerization and ‘click’ chemistry. The copolymers undergo self-assembly to form spherical micelles with diameters between 100 and 200 nm and a pH-trigger capability at pH values from 5.8 to 6.2. The micelles enabled DOX to be released at pH 5.0 at a much higher rate than at pH 7.4. Studies on cellular uptake revealed selective internalization of the DOX-loaded nanomicelles into HeLa cells where they can be imaged fluorometrically. Quantitative analysis of the green fluorescence indicated that the FITC-labeled micelles possess a transfection efficiency of about 79% while that of the nanomicellles with folate is only ∼40% under the same conditions. Confocal laser scanning microscopy indicates that the micelles invade the lysosome of HeLa cells and that the DOX released by micelles causes strong cell lethality. In our preception, this work provides useful insights in terms of designing multifunctional drug carriers and of improving the applicability of copolymer micelles for drug delivery systems.

The principal problem in the area of drug delivery is achieving better selectivity and controllability. A new core–shell nanoparticle composite (denoted MSN@Tf@Polymer) with dual-pH-sensitivity has been prepared as a drug carrier for intracellular drug delivery and release. MSN@Tf@Polymer consists of mesoporous silica nanoparticles (MSN), green-transferrin (Tf) and diblock copolymer (poly-2-diisopropylamino ethylmethacrylate-b-methoxy-poly ethyleneglycol: mPEG45-PDPAn). The core–shell structure is self-assembled layer by layer. Results show that nearly 80% doxorubicin hydrochloride (DOX) loaded in MSN@Tf@Polymer could be released in 5 h at pH 5.0, which is an improvement from the results obtained at pH 6.5 and pH 7.4. MTT assay and fluorescence inversion microscope experiments indicate that MSN@Tf is successfully taken up by liver cancer cells (Huh7) without apparent cytotoxicity, and Tf has strong intensity of fluorescence for subcellular localization. Confocal laser scanning microscopy (CLSM) experiments indicate that MSN@Tf@Polymer is able to enter the lysosome of the tumor cells. Furthermore, cell apoptosis experiments prove that DOX loaded in MSN@Tf@Polymer has the best anti-tumor effect compared with free DOX and DOX in bare MSN. MSN@Tf@Polymer has high biocompatibility, enhanced drug loading, site-specific delivery and in situ stimulus release and will also hopefully be applied as an intracellular drug delivery system.

One important thing in tumor chemotherapy is to develop the targeting, precise timing, and quantitative drug delivery/release system. According to the weak acid of tumor extracellular environment, a pH-sensitive bola-type triblock copolymer (PEG m -PDPA n -PEG m ) was synthesized and mixed with phospholipid to form functional hybrid liposomes (liposome@Bola). When compared to pure liposome, the stability of the liposome@Bola was enhanced greatly and the drug leakage was inhibited at pH 7.4. However, under pH 6.0, the drug released quickly through the nanopores on the lipid bilayer created by the escape of copolymers. Under a strongly acidic environment, the drug release of liposome@Bola could be blocked again due to the coverage of free copolymers. The kinetic curves of drug release had been modeled by using some frequently used models. It was found that the release of liposome@Bola under pH 6.0 was biphasic with a slow release by means of membrane permeation and a rapid second phase which was released through nanopores on liposome membrane. The results indicated that the pH-responsive liposome@Bola could be expected to be a good potential in controllable drug delivery system.

Photo-responsive materials with adjustable self-assembly morphologies and tunable rheological properties have attracted widespread interests of researchers in recent years because of their potential applications in controlled release, microfluidics, sensors, and so forth. In this paper, a series of UV-sensitive anisotropic fluids were prepared by combining trans-ortho-methoxycinnamate (trans-OMCA, in its salts form) and cationic Gemini surfactant propanediyl-α, ω-bis (N-dodecyl-N, N-dimethylammonium bromide) (12-3-12·2Br−) based on the research of self-assembly behaviors of the mixed system. The photo-responsive behaviors of anisotropic fluid formed in 12-3-12·2Br−/trans-OMCA/H2O system including macroscopic phase transition, microstructure transformation, rheological property, molecular interaction and isomerization degree of trans-OMCA were investigated by various techniques including UV-vis spectrum, rheology measurement, 1H NMR and 2D NOESY spectrum, transmission electron microscopy (TEM), polarized optical microscopy (POM), and dynamic light scattering (DLS). It is proved that upon exposure to UV-light, ortho-methoxycinnamate (OMCA) undergoes a photo-isomerization from trans form to cis form, which results in geometry transitions of the 12-3-12·2Br−/OMCA aggregates accompanied by a continuous phase separation and combination macroscopically; both proportion and concentration of OMCA in anisotropic solution have great influences on the photo-responsive behaviors of the system including the durations of UV irradiation and isomerization degrees of OMCA at the phase transition points. The photo-responsiveness of this smart fluids and the quantitative analysis are expected to provide reference for academic research or practical application in the fields of biomedicine, soft matters, food engineering and sunscreen.

Air pollution has become increasingly serious. Fine particulate matter (PM2.5) is the most well-known air pollutant, which leads to some common respiratory diseases when inhaled into the lungs to certain concentration. However, there is a lack of research on the process of dynamically monitoring the real-time effect of nanoparticles on the pulmonary surfactant monolayer. In this study, the DPPC/DPPG monolayer is prepared by the Langmuir method to simulate the lung surfactant monolayer during respiration and the carbon nanoparticles are introduced to the monolayer under different surface pressures to simulate the real dynamic process of inhaling nanoparticles during breathing. The effect of carbon nanoparticles on the surface behavior of DPPC/DPPG monolayer in real-time was examined in details by a combination of surface pressure (π)-area (A) isotherms, compressibility modulus (Cs-1)-surface pressure (π) isotherms and the Brewster angle microscopy (BAM). The results have shown that the introduction of carbon nanoparticles under different surface pressures affects the properties of lipid monolayers. The added carbon nanoparticles under lower surface pressure are easy to penetrate the lipid molecules to inhibit monolayer phase transition. When the carbon nanoparticles are introduced to the monolayer under higher surface pressure, they tend to self-aggregate to reduce the monolayer stability rather than interact with lipid tail chains. This work not only confirms the exotic hydrophobic carbon nanoparticles retain in the DPPC/DPPG monolayer irreversibly and affect the surface behavior of monolayer during respiration, but also opens a new idea for real-time monitoring of the effects of PM2.5 on lung health.

Oxygen-containing functional groups have strong effect on the electrochemical capacitive behavior of carbon electrodes and have been subjected to many experimental investigations. However, there are relatively few theoretical reports on the relation between the oxygen-containing functional groups and the capacitance of carbon supercapacitors. In this study, we present a simple molecular model to describe electric double layer (EDL) in the presence of Faradaic reactions. We find that electrodes modified with oxygen functional groups increase the Faradaic capacitance but have relatively little influence on the EDL capacitance. The theoretical predictions agree quantitatively with experimental observations. We hope that this joint model by combining quantum DFT and classical DFT could provide a theoretical routine to study pseudocapacitors.

One growing issue is how to use the weakly acidic conditions in endosomes/lysosomes for designing highly pH-sensitive drug carriers to deliver chemotherapeutic drugs accurately. In this paper, pH-sensitive amphiphilic triblock copolymers PEG8-PDPAn-PEG8 (n = 30, 50 and 100) were synthesized. Micelles composed of the copolymers were found to enter into lysosomes using a lysosome tracker method. The pH-sensitivity makes the micelles stable at pH 7.4 but swell and become looser at pH 6.0 due to protonation. Then, doxorubicin (DOX) was efficiently encapsulated in the hydrophobic cores of the micelles and released continuously in a weakly acidic environment. Cell toxicity assays were carried out using 2 human cell lines (HEK293 and Huh7) and showed good cyto-compatibility. In vitro cell viability tests proved that the DOX-loaded micelles could be more efficiently taken up by Huh7 tumor cells than free DOX, as well as actively trigger intracellular DOX release. Furthermore, in addition to small molecules (DOX), the copolymer micelles could also deliver macromolecules (such as transferrin, which could not enter into cells by itself) into lysosomes/endosomes. These nontoxic and multifunctional micelles can serve as a promising treatment candidate for efficient intracellular drug delivery and real-time monitoring.

The moisturizing and frictional interactions between emulsion and skin have a significant influence on the moisturizing efficacy and sensory properties of cosmetics. To deeply understand the interactions, we developed a kind of wax emulsion with liquid crystal structure and studied their interactions with dry, semi-moist and fully-moist skin. The moisturizing interaction was studied by using skin hydration test and tape stripping analysis, and it was found that with the increasing of liquid crystal content in the emulsion, the skin hydration level increased, desquamation index decreased and number of cutaneous lines increased, suggesting the increased moisturizing effect and barrier function. The frictional interaction was studied by finger friction test, and it was found that firstly during and after the application of emulsion on skin, the frictional interaction followed the stribeck-curve rule of lubrication. Secondly, when changing the water content of the substrate skin, the frictional behavior of the whole system showed a bell-curve behavior. Both skin hydration and water amount in the interfacial film played role in the frictional interaction between emulsion and skin, and the frictional interaction mechanism between wax emulsion and finger skin with different type of skin was proposed. This was the first time to study and discuss the effect of skin moist status on the moisturizing and frictional interactions between cosmetic emulsion and skin. The findings were significant for the design of high quality personal care products.

Photoresponsive micellar systems with adjustable aggregate morphologies and rheological properties may be useful in a number of fields such as in microfluidics, controlled release, and sensors. However, the complexity and great difficulty of synthesising photosensitive molecules hamper their practical applications to a significant degree. In this study, we constructed a novel photoinduced self-assembly system by introducing the photoresponsive derivative trans-2-methoxy-cinnamate (trans-OMCA) into the gemini surfactant N,N′-bis(dodecyldimethyl)-1,2-ethane diammonium dibromide (12-2-12·2Br−) solutions. The system displays abundant phase behaviors, and the long worm-like micelles, vesicles, as well as an aqueous two-phase system (ATPS) are observed in the 12-2-12·2Br−/trans-OMCA mixed system even at lower surfactant concentrations. The UV-responsive behavior of the formed vesicles and the worm-like micelles is investigated systematically. The results have shown that OMCA undergoes photoisomerization from the trans-form to the cis-form through UV light irradiation that alters the molecular packing at the micellar interface and thus leads to the transformation of micellar morphologies. The long worm-like micelles will turn into much shorter units when the sample is exposed to 365 nm UV light accompanied by a decrease in solution viscosity by more than an order of magnitude. The formed vesicle system, however, can be utilized to generate a multi-state self-assembly structure, including a worm-like micelle and a small spherical micelle, depending on the UV irradiation time. The morphologies of micelles in a 12-2-12·2Br−/trans-OMCA mixed system can be tailored by adjusting the system composition and the duration of UV light irradiation. Correspondingly, the rheological behavior of the 12-2-12·2Br−/trans-OMCA mixed system can be purposely tuned. The light-induced system with abundant self-assembly behaviors and tunable rheological properties would widen the potential application of gemini surfactants in drug delivery, smart fluids, and materials science.

The effect of chitin nanoparticles on surface behavior of lipid systems containing dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) is studied by surface pressure (π)-area (A) isotherms, polarization-modulation infrared reflection absorption spectroscopy (PM-IRRAS), Brewster angle microscopy (BAM). The variation of surface behavior of DPPC/DPPG monolayers is induced mainly by electrostatic interactions between nanoparticles and head groups of phospholipids. At lower surface pressure, nanoparticles can penetrate into the monolayers and the positive charges carried by nanoparticles benefits the enrichment of phospholipid molecules at surface, which not only increases the mean molecular area but also hinders the formation of phospholipid liquid-condensed (LC) phase. However, when surface pressure is higher, the nanoparticles flee away from the surface and some of the phospholipid molecules are pulled out of the monolayers together to the subphase and decrease the order degree of the monolayers. Moreover, nanoparticles can destroy the hydrogen-bond between water molecules and phosphate head groups and thus lead to the dehydration of phosphate groups. This work confirms that chitin nanoparticles can affect the surface behavior of DPPC/DPPG monolayers. Furthermore, the results obtained using mixed monolayer containing two major lung surfactants DPPC/DPPG and nanoparticles will be helpful for deep understanding the harm of PM2.5 to lung health.

The structure and number of air-voids in concrete can greatly affect the macroscopic performance of concrete. Therefore, the development of highly efficient concrete air content regulators, such as air-entraining agents or defoamers, is important. In this work, one novel block phenyloxy polyether with different propylene oxide (PO) units was successfully synthesized, and this kind of surfactants could be used as air-entraining agents or defoamers by controlling the ratio and position of PO in the polymer structure. The structures of these surfactants were verified by 1H NMR and infrared spectroscopy. Results of foamability and foam stability tests of these surfactants in water solutions indicated that the position and ratios of PO in the polymer structure have a remarkable effect on the foam properties of the surfactants. When these surfactants were applied to cement mortar, surfactant S4 with PO units adjacent to benzene ring group exhibited excellent air entrainment performance, whereas surfactants S8 and S9 with PO units at the end of the polymer showed obvious defoaming ability. The surface activity, adsorption and rheological properties were also tested to understand this type of surfactants. The results of concrete application and mechanism study showed that this type of surfactant had great potential for practical application.