Synthesis, Characterization of New Polyamides Bearing Triarylamine for Lightemitting Diodes

In this work, new di-acid monomers 4, 4’-di-carboxillic-4”-bromo-2”, 6”-dimethyl triphenylamine (Ma), 4, 4’- di-carboxylic -4”-chloro-2”, 6”-dimethyl triphenylamine (Mb) and 4, 4’- di-carboxylic -2”,4”-dichloro-6”-methyl triphenylamine (Mc) were synthesized by reaction of p-cyanobenzofluride with three different aromatic amines (4-bromo,2,6-dimethyl aniline, 4-chloro,2,6-dimethyl aniline and 2,4 dichloro, 6- methyl aniline ) via aromatic nucleophilc substitution method to form three di cyano intermediates 4, 4’-Dicyano-4”-bromo-2”, 6”-dimethyl triphenylamine (Da), 4, 4’-dicyano-4”-chloro-2”, 6”-dimethyl triphenylamine (Db) and 4, 4’-dicyano-2”,4”-dichloro-6”-methyl triphenylamine (Dc) which form final di-carboxylic monomers after alkaline hydrolysis. Finally, these monomers react with two different aromatic di amines, phenylene diamins and benzidine respectively via polycondensation reaction to form final polyamides 4"-bromo-2", 6"-dimethyl-triphenylamine-4, 4'-polyphenylbenzamide (Pa), 4”-chloro-2”,6”-dimethyl- triphenylamine-4,4'-polyphenylbenzamide (Pb), 2”,4”-dichloro-6”-methyl-triphenylamine 4,4'- polyphenylbenzamide (Pc),4"-bromo-2",6"-dimethyl triphenylamine-4,4'- polyphenylbiphenylamide (Pd), 2”,4”-dichloro-6”-methyl-triphenylamine-4,4’-polyphenylamide (Pf). The chemical structure of these polymers characterized by FTIR and NMR techniques. All the results of polyamides showed excellent solubility in most polar solvents to form strong thin films. The polyamides possess a good thermal stability with height glass transition temperatures (Tg). Polyamides in DMSO solvent gave strong photoluminescence PL. Thin casting films of these polyamides in cyclic voltammetry (C.V) on glass base of iridium-tin oxide (ITO) as working electrode in dry CH3CN solvent contains 0.1 M of tetrabutylantimoneperchlorate (TBAP) as an Electrolyte gave one redox wave.

Development of the Biomaterials Technology for the Infection Resistance

Infections caused by microbial proliferation are one of the common issues and serious threats to the medical care, and they usually result in disease spread. Therefore, it is a significant issue for developing the antiinfective biomaterials to control this problem, according to the specific clinical application. Meanwhile, all their properties, the best anti-infective performance, the safe biocompatibility and the appropriate tissue interactions must be conformed to each other. At present, technologies are developing novel biomaterials and surfaces endowed with anti-infective properties, relying either on bactericidal or anti-biofilm activities. This review focuses on thoroughly summarizing numerous kinds of antibacterial biomaterials, including the antibacterial matrix biomaterials, antibacterial coatings and films, nanostructured materials and antibacterial fibers. Among these strategies, the utilization of bio-glass base and graphene base antibacterial matrix, and their effects on the antibiosis mechanism were emphatically discussed. Simultaneously, the effects and mechanisms of nano-coated metallic ions are also mentioned. Overall, there is a wealth of technical solutions to contrast the establishment of an implant infection. The lack of well-structured prospective multicenter clinical trials hinders the achievement of conclusive data on the efficacy and comparative performance of antibacterial biomaterials.

The role of poly(acrylic acid) in conventional glass polyalkenoate cements

Glass polyalkenoate cements (GPCs) have been used in dentistry for over 40 years. These novel bioactive materials are the result of a reaction between a finely ground glass (base) and a polymer (acid), usually poly(acrylic acid) (PAA), in the presence of water. This article reviews the types of PAA used as reagents (including how they vary by molar mass, molecular weight, concentration, polydispersity and content) and the way that they control the properties of the conventional GPCs (CGPCs) formulated from them. The article also considers the effect of PAA on the clinical performance of CGPCs, including biocompatibility, rheological and mechanical properties, adhesion, ion release, acid erosion and clinical durability. The review has critically evaluated the literature and clarified the role that the polyacid component of CGPCs plays in setting and maturation. This review will lead to an improved understanding of the chemistry and properties of the PAA phase which will lead to further innovation in the glass-based cements field.

Development of an atomic force microscope closed fluid cell for tribological investigations of large samples in chemically aggressive environments

Many atomic force microscopes (AFM) are nowadays equipped with closed fluid cells. Most of these closed fluid cells have small volume, limiting the maximum sample size, and, furthermore, do not allow for investigations in chemically aggressive environments such as solvents. The closed fluid cell for MFP-3D, the atomic force microscope from Asylum Research, Santa Barbara, CA, has a glass base and is mainly intended for investigations of flat transparent biological samples. Starting from the MFP-3D closed fluid cell, a fluid cell tailored for investigations in tribologically relevant environments, e.g. at extreme mechanical and chemical conditions which may vary with time, was developed. Samples of various shapes and sizes can thus be investigated in controlled environments, be they fluid (e.g. solvents) or gaseous (e.g. corrosive gases). First results of AFM nanotribology experiments using this fluid cell are presented. Among the systems of interest are additives diluted in solvents adsorbing to surfaces and spreading and persistence of ionic liquids on tribologically stressed surfaces.