Responsive Poly(acrylic acid) and Poly(N-isopropylacrylamide) Monoliths by High Internal Phase Emulsion (HIPE) Templating

• Published in: Macromolecular chemistry and physics Vol. 212; no. 19; pp. 2151 - 2158
• Main Authors: Kovačič, Sebastijan, Jeřabek, Karel, Krajnc, Peter
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 04-10-2011; WILEY‐VCH Verlag; Wiley
• Subjects: Applied sciences; Crosslinking; Discs; Disks; emulsion templating; Emulsions; Exact sciences and technology; Holes; monoliths; Organic polymers; Physicochemistry of polymers; polyHIPE; Polymers with particular structures; Polystyrene resins; porous polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts; Scaffolds; stimuli responsive polymers; Transport properties; Monolithic column; Temperature effect; Experimental study; Acrylamide derivative polymer; polyHIPE; stimuli responsive polymers; Polyelectrolyte; Free radical polymerization; porous polymers; Emulsion polymerization; Morphology; Preparation; Acrylic acid polymer; Crosslinked polymer; pH; Styrene polymer; Porosity; Liquid permeability; emulsion templating; monoliths
• ISSN: 1022-1352; 1521-3935; 1521-3935
• DOI: 10.1002/macp.201100229

High internal phase emulsions are used to prepare cross‐linked polystyrene/poly(acrylic acid) (PS/PAA) and polystyrene/poly(N‐isopropyl acrylamide) (PS/PNIPAM) monoliths with a polystyrene scaffold and acrylic domains inside the cavities of the scaffold. Acrylic acid or NIPAM are included in the aqueous phase of a high internal phase emulsion, while the oil phase includes styrene. Polymerisation of such high internal phase emulsions (HIPEs) yields macroporous polymers (polyHIPEs) with a scaffold composed of cross‐linked polystyrene and domains of cross‐linked poly(acrylic acid) or cross‐linked poly(NIPAM) positioned inside the cavities of the polystyrene skeleton. Monolithic discs are shaped from PS/PAA and PS/PNIPAM polyHIPEs in order to study the dependence of flow resistance through the discs in relation to pH or temperature changes. The amount of acrylic component in the aqueous phase and the degree of cross‐linking prove to be the most influential on the pressure drops of columns with monolithic discs. The temperature influences the resistance properties in the case of PS/PNIPAM material. Inverse size exclusion chromatography experiments confirm the pH dependent structure of the polymeric monoliths.
High internal phase emulsions are used to prepare monoliths with polyacrylic components inside the cavities of a polystyrene skeleton. These materials exhibit responsive behavior in terms of temperature‐ or pH‐dependent flow through the materials.