New Membrane-Forming Aromatic Co-Poly(amide-imide)s: Influence of the Chemical Structure on the Morphological, Thermal and Transport Properties

Polymer film membranes are used to solve specific separation problems that dictate structural requirements. Structural and morphological parameters of film membranes based on glassy polyheteroarylenes can be controlled in the process of preparation from solutions that opens up prospects for obtaining structured membranes required for targeted separation. In the case of aromatic poly(amide-imide)s, the possibility of controlling film formation and structure virtually has not been studied. In the present work, a series of homologous co-poly(amide-imide)s differing in the number of repeating units with carboxyl-substituted aromatic fragments was synthesized by polycondensation. Comparative analysis of the processes of formation of membranes with different morphologies based on these polymers under equal conditions was performed. New information was obtained about the influence of the amounts of carboxyl groups and the residual solvent on structural properties of asymmetric membranes. The influence of these factors on transport properties of dense membranes under pervaporation conditions was studied. It was demonstrated that in the case of carboxyl-containing poly(amide-imide)s, the domains formed during film preparation had a significant effect on membrane properties.

Incorporation of Various Nanoclays in Semi-refined Carrageenan Film Composite

In current investigation, various commercial nanoclays with different level of hydrophilicity i.e., hydrophilic bentonite (HB), cloisite 10A, and cloisite® 30B were incorporated to a hydrophilic semi-refined carrageenan (SRC) films to observe their presence in film matrix in regards with the final film’s properties. High shear mixing and sonication were applied to the film preparation to obtain high dispersion of nanoclays in the matrix. As expected, the hydrophilic clay showed better dispersion within the matrix as shown in Energy Dispersive X-Ray Spectroscopy (EDS) image. The more hydrophilic clay inclusion resulted in higher tensile strength, while the more hydrophobic resulted in higher stiffness of the films. The water vapour permeability was decreased in corresponded to the more hydrophobic clay incorporated, and the thermal properties of the films were overall enhanced by the nanoclays reinforcement. In general, nanoclays incorporation in SRC film improved the overall properties of the SRC film.

Solid State Humidity Sensors

A variety of humidity sensors have been developed to address the problem of humidity measurement in instrumentation, agriculture and systems which are automatic. Various types of humidity sensors have been reviewed along with their mechanisms of humidity detection. Thin and thick film preparation processes are quite flexible. This flexibility provides advantages over other technologies. After comparing all the aspects of different humidity sensors, it has been observed that there are still some shortcomings left, which need to be removed to enhance the humidity sensing capability, recovery and response times of the sensor elements.

Water effect on the morphology and magnetic properties of poly(3-hexylthiophene)

Poly(3-hexylthiophene) magnetics characteristics and morphologic prepared in acetonitrile solution by electrochemical techniques have been studied, and the results are reported. The results indicate that the films prepared in small amounts of water in the electrolyte solution show significantly different morphology and magnetic behavior. The differences in these properties are explained in terms of different functional groups introduced during polymers film preparation.