A temperature/pH-sensitive introducing monomer-dimethyl-benzyl-(2-methacryloxyethyl) ammonium bromide (DMBMAAB) was synthesized through the reasonable design of functional groups

combining the hydrophilic cation and hydrophobic benzyl on a same monomer. The structure and purity of DMBMAAB was characterized by 1H-NMR analysis and liquid chromatography analysis respectively.The copolymer P(DMBMAAB-co-AM) of DMBMAAB and acrylamide(AM) was synthesized through the free radical polymerization in aqueous solution.The P(DMBMAAB-co-AM) was characterized by 1H NMR analysis and elemental analysis.The aqueous solution of P(DMBMAAB-co-AM) exhibits a different temperatureresponse property compared to poly(N-isopropylacrylamide) (PNIPAAm)

which exhibits a lower critical solution temperature(LCST) at 32℃

however the P(DMBMAAB-co-AM) exhibits a higher critical solution temperature(HCST).The transmittance and apparent viscosity (apparent property) changed evidently when heating the solution of P(DMBMAAB-co-AM) from 50℃ to 70℃.The pH-sensitive property of P(DMBMAAB-co-AM) is another difference compared PNIPAAm

which is sensitive to temperature but not pH-sensitive;the apparent property changed sharply when pH rose from 11 to 12- Moreover

the apparent property of P(DMBMAAB-co-AM) solution can respond to other environmental stimuli

such as surfactant (SDS) and salt (NaCl).The results indicate that P(DMBMAABcoAM) is a kind of novel functional material

which exhibits the properties of multifactor response

and the interaction between hydrophilic and hydrophobic groups in the chains and environmental condition were the main reason for the stimuli-responsive behavior.