PVA Networks Grafted with PDMS Branches

We describe a simple and efficient synthesis of poly(vinyl alcohol) (PVA) networks fitted with polydimethylsiloxane (PDMS) branches (PVA(netw)-g-PDMS). The syntheses were achieved in two steps: (1) Grafting by urethane linking PDMS carrying -NCO termini (PDMS-NCO) onto PVA fitted with a few (similar to 4) photoreactive acryl amide groups (PVAA,), followed by (2) Photocrosslinking the PVA(AA)-g-PDMS to PVA(netw)-g-PDMS. The use of the binary N-methyl-2-pyrrolidone/tetrahydrofuran (NMP/THF, 67/33) solvent system enabled the thermodynamically unfavorable mixing of hydrophobic PDMS branches with hydrophilic PVAA, backbones. The amphiphilic graft, PVA(AA)-g-PDMS, was characterized by H-1 NMR spectroscopy, and the final graft network, PVA(netw)-g-PDMS, by FTIR spectroscopy, DSC, and equilibrium swelling. The grafting of sufficient volumes of PDMS branches onto PVA(AA) yields cocontinuous hydrophilic/hydrophobic PVA/PDMS domains, whose existence was demonstrated by swelling in both water and hexanes. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5272-5277, 2009