Improvement of elasticity and strength of poly(N-isopropylacrylamide) hydrogels upon copolymerization with cationic surfmers

摘要: The mechanical properties of thermoresponsive homopolymer hydrogels based on N-isopropylacrylamide (NIPAAm) and copolymer gels NIPAAm two different cationic surfactant monomers (surfmers) were investigated. prepared without the aid any chemical cross-linker using γ-ray induced polymerization in aqueous micellar solution. Two surfmers used, reactive unit either being attached to polar head (H-surfmer) or hydrophobic tail (T-surfmer) molecule. (11-(Acryloyloxy)undecyl)trimethylammonium bromide (AUTMAB) was used as T-surfmer, (2-(methacryloyl)ethyl)dodecyldimethylammonium (MEDDAB) H-surfmer. stability investigated elongational flow measurements. It found that increases with increasing surfmer concentration gel. Hencky-strain at break eHmax true stress σHmax are clearly higher for than pure poly-NIPAAm (P-NIPAAm) gels. A hydrogel containing 1% (w/w) MEDDAB can be elongated up a nearly six times large, more twice large P-NIPAAm improved is explained by presence copolymerized aggregates, which act additional, stable cross-linking units. also shown T- H-type different. structure model correlating possible micelle structures derived from surface tension measurements presented.