Tuning the performance of aqueous photovoltaic elastomer gels by solvent polarity and nanostructure development

In this study, a sulfonated pentablock ionomer is considered for use as an aqueous gel electrolyte in photovoltaic elastomer gels (PVEGs) containing photosensitive dyes. Depending on the casting solvent employed, these materials order into different nanoscale morphologies, some of which inherently consist of a continuous pathway through which ions and other polar species are able to diffuse, while others transform into continuous channels upon exposure to water. Here, we examine the effect of solvent polarity during film casting, vapor annealing, and liquid immersion on block ionomer morphology and PVEG photovoltaic performance. Casting the block ionomers from a mixed nonpolar/polar solvent promotes the formation of dispersed ion‐rich spherical microdomains. Alternatively, the use of a single polar solvent produces coexisting nonpolar cylinders and lamellae. Exposure of either morphology to polar solvent vapor causes the block ionomers to restructure into a lamellar morphology, whereas exposure of dispersed ion‐rich microdomains to water induces a transformation to an irregular morphology composed of continuous ionic channels, which provide an effective pathway for ion diffusion and, consequently, the highest photovoltaic efficiency. In addition to their photovoltaic efficacy, these aqueous gels possess improved mechanical properties (in terms of tensile strength and elastic modulus) in the presence of photosensitive dyes. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 85–95     

SOLVENT QUALITY AND SOLUTION BEHAVIOR OF NYLON 12

The refractive index increment,dynamic and static laser light scattering,intrinsic viscosity[η]and Huggins constant(K_H)of nylon 12 have been measured in m-cresol and sulphuric acid/water system at 10-60℃.The intrinsic viscosity,R_H,R_g,A_2,and(~2)~(1/2)(calculated from viscosity data)and"a"values of nylon 12 are found to be higher in m-cresol than in sulphuric acid.All these parameters decrease with the increase in water contents in sulphuric acid.The refractive index increment,K_H and activation energy show an opposite trend to that of[η].The intrinsic viscosity,R_H,R_g,A_2, and(~2)~(1/2) have maximum values around 30-40℃in sulphuric acid/water system,whereas in m-cresol they fall at about 20℃.It has been concluded that the variation in size,interaction parameter(second virial coefficient),[η]and K_H of the polymer solutions with the alteration in solvent composition and temperature are the out come of change in thermodynamic quality of solvents,selective adsorption,hydrogen bonding and conformational transitions.It has also been concluded that the increase in temperature first enhances the quality of the solvent,encourages hydrogen bonding and specific adsorption, and then deteriorates,bringing conformational transitions in the polymer molecules.However,the addition of water to sulphuric acid continuously deteriorates the solvent quality.This characteristic of the solvent system brings conformational changes in the polymer especially at low temperatures.     

Improving the Thermal Behavior and Flame-Retardant Properties of Poly(o-anisidine)/MMT Nanocomposites Incorporated with Poly(o-anisidine) and Clay Nanofiller

The synthesis of MMT and poly(o-anisidine) (MMT/POA) clay nanocomposites was carried out by using the chemical oxidative polymerization of POA and MMT clay with POA, respectively. By maintaining the constant concentration of POA, different percentage loads of MMT clay were used to determine the effect of MMT clay on the properties of POA. The interaction between POA and MMT clay was investigated by FTIR spectroscopy, and, to reveal the complete compactness and homogeneous distribution of MMT clay in POA, were assessed by using scanning-electron-microscope (SEM) analysis. The UV–visible spectrum was studied for the optical and absorbance properties of MMT/POA ceramic nanocomposites. Furthermore, the horizontal burning test (HBT) demonstrated that clay nanofillers inhibit POA combustion.     

Photophysical Investigations of Carmoisine Interacting with Conventional Cationic Surfactants Under Different pH Conditions

The present study describes the extent of interactions of an efficient food dye, Carmoisine (CAR), with conventional cationic surfactants, hexadecyltrimethylammonium bromide, and ethylhexadecyldimethylammonium bromide (EHDAB). The study was carried out by quantifying the spectral changes of CAR as a function of premicellar to postmicellar surfactant concentrations at various pH conditions. The quantification of CAR molecules entrapped by cationic micellar systems has been estimated with the help of mathematical models. Binding parameters of each surfactant were calculated using differential spectroscopic method. The enhanced solubilization of dye by switching the pH was observed. In support of the electrostatic forces, the larger and more hydrophobic head group favors the promising solubilization of CAR in the outer region of the micellar interior. These findings extend the proficiency of dye molecule as a reporter for sensing electrostatic environment in lipidic membranes and related organized assemblies.     

A review on use of TRNSYS as simulation tool in performance prediction of desiccant cooling cycle

Journal of Thermal Analysis and Calorimetry - Solid desiccant-assisted cooling and dehumidification systems are becoming very popular nowadays for maintaining the required thermal comfort in...     

One‐Pot Synthesis of Redox‐Responsive Polymers‐Coated Mesoporous Silica Nanoparticles and Their Controlled Drug Release

A versatile one‐pot strategy for the preparation of reversibly cross‐linked polymer‐coated mesoporous silica nanoparticles (MSNs) via surface reversible addition–fragmentation chain transfer (RAFT) polymerization is presented for the first time in this paper. The less reactive monomer oligo(ethylene glycol) acrylate (OEGA) and the more reactive cross‐linker N,N′‐cystaminebismethacrylamide (CBMA) are chosen to be copolymerized on the external surfaces of RAFT agent‐functionalized MSNs to form the cross‐linked polymer shells. Owing to the reversible cleavage and restoration of disulfide bonds via reduction/oxidation reactions, the polymer shells can control the on/off switching of the nanopores and regulate the drug loading and release. The redox‐responsive release of doxorubicin (DOX) from this drug carrier is realized. The protein adsorption, in vitro cytotoxicity assays, and endocytosis studies demonstrate that this biocompatible vehicle is a potential candidate for delivering drugs. It is expected that this versatile grafting strategy may help fabricate satisfying MSN‐based drug delivery systems for clinical application.

     

Effect of Sodium Alkanoates on Micellization of Dodecylbenzyldimethylammonium Chloride in Aqueous Medium

The present study deals with the interaction of sodium alkanoates viz. sodium acetate, sodium propionate, sodium butanoate, sodium hexanoate and sodium benzoate on the micellization of dodecylbenzyldimethylammonium chloride using conductometeric and flourscence quenching experiments carried out at 25°C. The analysis has been made through study of variation of critical micelle concentration (cmc), degree of counterion binding (β), aggregation number (N), and micropolarity with the concentration of these hydrophobic salts. The differentiation between the effects of hydrophobic and inorganic salts was made by comparing the above results with the influence of NaCl on cmc, β, and N.