(296c) Photocrosslinked Styrene-Butadiene-Styrene (SBS) Polymer Gels for Biomedical Applications

Styrene-butadiene-styrene (SBS) block copolymer is a widely studied block copolymer with well-known mechanical properties and flexibility. Crosslinking of SBS for the synthesis of SBS gels, and hydrophobic nature of SBS has not been investigated for biomedical applications extensively in previous studies. In this study, we have investigated real time photocrosslinking of SBS with rheometer. Incorporation of silica nanoparticles and a hydrophilic polymer into SBS gel has also been considered for the synthesis of a composite gel with nanostructured domains and multifunctional properties. SBS has reactive vinyl groups which can be crosslinked with UV radiation. Chemical crosslinking was induced by Dithiothreitol (DTT), and eosin Y was used as photoinitiator. Storage modulus (G’) and loss modulus (G”) of solutions with higher concentrations of crosslinker or eosin showed transitions from predominantly viscous behavior (G” > G’) to elastic behavior (G’ > G”) at earlier photopolymerization times. These results are also consistent with the swelling studies where largest swelling ratios were obtained with lower concentrations of photoinitior and crosslinker in the solution. The composite has been further characterized with FTIR and SEM. The amphiphilic nature of the composite synthesized here could be utilized for the delivery drug molecules with altered hydrophobicities, or for various other applications, where the delivery of agents through mediums would otherwise not be compatible with polar agents.