Nanoporous Thermosetting Polymers

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• 作者：Vijay I. Raman and Giuseppe R. Palmese
• 刊名：Langmuir
• 出版年：2005
• 出版时间：February 15, 2005
• 年：2005
• 卷：21
• 期：4
• 页码：1539 - 1546
• 全文大小：965K
• 年卷期：v.21,no.4(February 15, 2005)
• ISSN：1520-5827

文摘

Potential applications of nanoporous thermosetting polymers include polyelectrolytes in fuel cells,separation membranes, adsorption media, and sensors. Design of nanoporous polymers for such applicationsentails controlling permeability by tailoring pore size, structure, and interface chemistry. Nanoporousthermosetting polymers are often synthesized via free radical mechanisms using solvents that phaseseparate during polymerization. In this work, a novel technique for the synthesis of nanoporous thermosetsis presented that is based on the reactive encapsulation of an inert solvent using step-growth cross-linkingpolymerization without micro/macroscopic phase separation. The criteria for selecting such a monomer-polymer-solvent system are discussed based on FTIR analysis, observed micro/macroscopic phase separation,and thermodynamics of swelling. Investigation of resulting network pore structures by scanning electronmicroscopy (SEM) and small-angle X-ray scattering following extraction and supercritical drying usingcarbon dioxide showed that nanoporous polymeric materials with pore sizes ranging from 1 to 50 nm canbe synthesized by varying the solvent content. The differences in the porous morphology of these materialscompared to more common free radically polymerized analogues that exhibit phase separation were evidentfrom SEM imaging. Furthermore, it was demonstrated that the chemical activity of the nanoporous materialsobtained by our method could be tailored by grafting appropriate functional groups at the pore interface.