Amphiphilic thermoset elastomers from metal-free, click crosslinking of PEG-grafted silicone surfactants

Abstract

The hydrophobicity of silicone elastomers can compromise their utility in some biomaterials applications. Few effective processes exist to introduce hydrophilic groups onto a polysiloxane backbone and subsequently crosslink the material into elastomers. This problem can be overcome through the utilization of metal-free click reactions between azidoalkylsilicones and alkynyl-modified silicones and/or PEGs to both functionalize and crosslink silicone elastomers. Alkynyl-functional PEG was clicked onto a fraction of the available azido groups of a functional polysiloxane, yielding azido reactive PDMS-g-PEG rake surfactants. The reactive polymers were then used to crosslink alkynyl-terminated PDMS of different molecular weights. Using simple starting materials, this generic yet versatile method permits the preparation and characterization of a library of amphiphilic thermoset elastomers that vary in their composition, crosslink density, elasticity, hydrogel formation, and wettability. An appropriate balance of PEG length and crosslink density leads to a permanently highly wettable silicone elastomer that demonstrated very low levels of protein adsorption. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1082–1093