Microstructure and solvent distribution in cross-linked diblock copolymer gels

Gels were created by irradiating poly(α-methylstyrene-block-isoprene) (PaMS-I) and poly(vinylferrocenium triflate-Wocfc-isoprene) (PVFT-I) copolymers with an electron beam and swelling the resulting cross-linked solids in good solvents. The radiation cross-links the polyisoprene (PI) block, induces chain scission of the poly(α-methylstyrene) block (PaMS), and has no effect on the poly(vinylferrocenium triflate) (PVTF) block. After extraction of un-cross-linked chains, the PaMS-I gels comprise sol vent-filled, open channels inside a swollen PI network, while the swollen PVFT-I gels comprise channels of solvated PVFT chains inside a swollen PI network, The dependence of the structure, composition, and cross-linking density of the swollen microphases on radiation dose is determined by combining small-angle neutron scattering experiments with conventional gel characterization methods.