(751f) Bio-Mimetic and Bio-Inspired Membranes: Preparation and Applications

The notion of mimicking natural structures in the synthesis of new structural materials has generated enormous interest and has yielded remarkable practical advances. ?Learn from nature?, our group introduces biomineralization and bioadhension into the fabrication of dense membranes, which are employed in pervaporation and gas separation. Hydrophilic and hydrophobic polymer based polymer-inorganic hybrid membranes have fabricated respectively through the in-situ formation of silica nanoparticles within polyvinyl alcohol (PVA) and poly dimethylsiloxane (PDMS) host matrix enabled by the templating and catalysis of protamine, and the size, morphology as well as spatial distribution of silica nanoparticles are conveniently controlled. Incorporating silica particles destroys the polymer packing, decreases the glass transition temperature (Tg) and increases the fractional free volume. In order to ensure the facile membrane fabrication and suppress the aggregation of inorganic particles within the membranes, we consequently fabricate hybrid membranes whose polymer matrix coincidently serves as the catalyst for inorganic precursor, and confined-space for the inorganic nanoparticles. The homogeneously distributed nanoparticles endow the membranes with appropriate free volume properties. This novel approach allows superior control of the nanoparitcles morphology and the membrane architecture, and hopefully it will establish a facile, efficient and generic new-generation platform for preparing a variety of polymer-inorganic nanocomposite membranes. Polydopamine as mussel-adhesive-mimetic material is firstly and successfully utilized to the ultra-thin (<100nm) composite membrane fabrication in our study, which can firmly adhere onto the porous substrate. The thickness and compactness of the skin layer are conveniently tuned by varying dipping conditions (dopamine concentration, soaking time, and pH values). The as-prepared membranes display strong interfacial binding strength, well-defined free volume characteristics. This facile, versatile, and efficient approach could be as a novel and promising platform for ultrathin composite materials fabrication. The as-prepared membranes are used in the pervaporative desulfurization of model gasoline and dehumidification of propylene and show superior performance. The effects of the operating parameters such as temperature, pressure, feed concentration and flow rate on the membrane separation performance are extensively investigated