Third-generation amphiphilic conetworks.: I.: Synthesis and swelling behavior of poly(N,N-dimethyl acrylamide)/polydimethylsiloxane conetworks

A strategy has been developed for the synthesis of novel amphiphilic co-networks (APCNs) of poly(N,N'-dimethyl acrylamide) (PDMAAm) and polydimethylsiloxane (PDMS) segments crosslinked with polyhydrosiloxanes. The synthesis proceeds in three steps in one pot (see Figure 2 for reactions and abbreviations): (1) the preparation of a charge containing three components (an asymmetric-telechelic macromonomer, MA-PDMS-V, plus two symmetric-telechelic crosslinkers, MA-PDMS-AIA and V-PDMS-V), (2) the free-radical terpolymerization of N,N-dimethyl acrylamide, MA-PDMS-V, and MA-PDMS-MA into a slightly crosslinked and soluble graft of a PDMAAm backbone carrying-PDMS-V branches, and (3) the crosslinking of PDMS branches with polyhydrosiloxanes. The effects of key experimental parameters (e.g., composition, molecular weights, and initiator and crosslinker concentrations) on synthesis details and swelling behavior have been studied. The water uptake/permeability of APCNs is significantly increased by the addition of homo-PDMAAm to graft charges, crosslinking of the graft, and, after the desirable morphology is stabilized, removing the homo-PDMAAm by water extraction. (c) 2006 Wiley Periodicals, Inc.