Two-phase partitioning bioreactors (TPPBs) have been recently demonstrated to be capable of using solid polymers as the absorbing/desorbing phase. In this paper, we examine the possibility of using a siloxane-based copolymer as this phase. Copolymers were prepared using vinyl terminated oligo(dimethylsiloxane-co-diphenylsiloxane), copolymerized with varying amounts of the comonomers ethylene glycol dimethacrylate (EGDMA), N-vinyl pyrrolidone (NVP), or acrylic acid (AA), via free radical polymerization. The absorption rate of phenol as a representative pollutant into these polymers from water was measured. The inclusion of a water-soluble comonomer resulted in swelling of the polymers in water, enhanced total phenol absorption, but reduced phenol diffusivity.