Pore Formation in Poly(divinylbenzene) Networks Derived from Organotellurium-Mediated Living Radical Polymerization

Macroporous cross-linked polymeric dried gets have been obtained by inducing phase separation in a homogeneous poly (divinylbenzene) (PDVB) network formed by organotellurium-mediated living radical polymerization (TERP). The living polymerization reaction of DVB with the coexistence of a nonreactive polymeric agent, poly(dimethylsiloxane) (PDMS), in solvent 1,3,5-trimethylbenzene (TMB) resulted in polymerization-induced phase separation (spinodal decomposition), and the transient structure of spinodal decomposition has been frozen by gelation. Well-defined macroporous monolithic dried gels with bicontinuous structure in the micrometer scale are obtained after removing PDMS and TMB by simple washing and drying. Inside the skeletons that comprise the macroporous structure, skeletal pores with various sizes in nanometer scale have also been found by gas sorption measurements. The skeletal pores are deduced to be formed by secondary phase separation in the skeletons due to the thermodynamic instability that arises in the separated phases during the polymerization. The properties of the macropores and the skeletal pores have been controlled by changing starting composition, molecular weight of PDMS, and reaction temperature.