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

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 Metal‐free click reactions between azidoalkylsilicones, alkynyl‐PDMS and alkynyl‐PEGs lead readily to hydrophilic silicone elastomers. Monoalkynyl‐functional PEGs were first clicked onto a fraction of the available azido groups of a functional polysiloxane backbone, yielding azido reactive PDMS‐g‐PEG rake surfactants. These polymers were then used to crosslink α,ω‐alkynyl PDMS of different molecular weights. Using a few simple starting materials, this generic yet highly versatile method permits the preparation and characterization of a library of amphiphilic elastomers and hydrogels.