Organic-Inorganic Hybrid Materials with Specific Solute and Gas Transport Properties for Membrane and Sensor Applications

Abstract

This paper is concerned with synthesis of hybrid materials for membrane applications. Examples of hybrid nanocomposites (type I) and hybrid polymers (type II) are presented. Dealing with type I, molecular sieves such as microporous silica beads or zeolite crystals were added to polymer matrices as an attempt to increase gas and vapor separation membrane performance. Also, specific organic molecules were inserted in a silica matrix as the active part of chemical sensors. Regarding type II materials, the arrangement at the molecular level of the organic and inorganic parts as well as their chemical composition have been investigated for facilitated transport of heavy metal ions or aminoacids in aqueous media, but also for separation of oxygen/nitrogen or volatile organic compounds from air. Processing of type II membranes is mainly based on the sol-gel method for which the synthesis of hybrid materials is undoubtedly one of the major advances. The specific advantages of this “chimie douce” method (low temperature chemical process, large variety of material precursors, material structure adaptability, and good film forming ability) are described here as a very suitable way to design and synthesize synthetic membranes with improved performance.