Emulsion templating has now emerged as effective method to synthesise macroporous polymers with tailored pore morphology and physical properties. High or Medium Internal Phase Emulsions (HIPEs or MIPEs) with a continuous phase consisting of or containing monomers are used as templates for the preparation of very high porosity macroporous polymers, called poly(merized)M/HIPEs. However, this method typically requires the use of large amounts of surfactants or particulate emulsifiers to stabilize the immiscible liquid phases and monomers and a crosslinker in the continuous minority phase to solidify the HIPE, which may not be desirable for biomedical applications. We will show that polyHIPEs with porosity greater than 75% can be produced from inverse (oil-in-water) HIPEs solely stabilised using suitably modified biocompatible biopolymers, such as gelatin, chitosan. The biopolymer was modified by grafting poly(N-isopropylacrylamide) from it and further grafting of oligo(aminoacid)s. The resulting copolymer acts simultaneously as emulsifier and thermoresponsive gelator and forms upon removal of the oil templating phase and water the bulk of the resulting polyHIPE. Upon addition of only a small amount of surfactant and by varying the polymer structure, concentration and internal phase volume ratio, different polyHIPEs with porosities of up to 99%, surface areas in excess of 300 m2/g and controlled pore interconnectivity can be formed. Moreover, the resulting polyHIPEs are thermoresponsive and injectable hydrogels, which remain intact when immersed into water at physiological temperature but do dissolve below their lower critical solution temperature, which is useful for various applications.

Thermoresponsive poly high internal phase emulsion hydrogels from inverse HIPEs: Potential injectable scaffolds

248th National Meeting (2014)

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