疏水改性智能水凝胶P(NIPA-co-DiAB)的合成及其温敏行为

以N-异丙基丙烯酰胺(NIPA)和N,N-双烯丙基苄胺(DiAB)为共聚单体、N,N-亚甲基双丙烯酰胺(BIS)为交联剂、十二烷基硫酸钠(SDS)为表面活性剂、过硫酸铵(APS)-四甲基乙二胺(TMEDA)为氧化还原引发体系，采用自由胶束交联共聚法合成了疏水基团为芳香基的疏水改性温敏性智能水凝胶P(NIPA-co-DiAB)。研究了DiAB摩尔分数(x(DiAB))对水凝胶溶胀性能的影响。 在初始溶胀阶段，随着x(DiAB)由0增大至3%，P(NIPA-co-DiAB)水凝胶的溶胀行为由Fickian扩散转变为non-Fickian扩散。x(DiAB)分别为0、1%、2%和3%时，P(NIPA-co-DiAB)水凝胶的平衡溶胀率SR0在蒸馏水中分别为63.6、93.5、141.6和167.4，在0.01 mol/L SDS溶液中分别为63.1、71.0、59.0和77.5，在CTAB溶液中分别为37.6、42.2、44.1和60.0，在Triton X-100溶液中分别为30.9、49.4、68.5和88.3。 结果表明，P(NIPA-co-DiAB)水凝胶的(SR0)大于PNIPA水凝胶，且在蒸馏中比在0.01 mol/L表面活性剂溶液中要大。 加入0.01 mol/L Triton X-100、CTAB或SDS后，PNIPA水凝胶的体积相变温度或较低临界溶解温度(LCST)由32.5 ℃分别增加至35.4、45.6和80 ℃。P(NIPA-co-DiAB)水凝胶的LCST由32.0～32.5 ℃分别增加至34.7～35.6 ℃、45.8~46.2 ℃和80 ℃。 加入表面活性剂能增加P(NIPA-co-DiAB)水凝胶的体积相变温度，高的体积相变温度与DiAB含量无关。

Synthesis and Thermoreversible Swelling Behavior of Hydrophobically Modified Intelligent Hydrogels P(NIPA-co-DiAB)

Temperature-sensitive hydrogels P(NIPA-co-DiAB) with aromatic group as hydrophobe was were prepared by free radical micellar crosslinking copolymerization with N-isopropyl acrylamide(NIPA) and N,N-dially benzylamine(DiAB) as comonomers, N,N-methylene-bis-acrylamide(BIS) as crosslinker, sodium dodecyl sulfate(SDS) as surfactant and ammonium persulfate(APS) tetramethylethylenediamine(TMEDA) as initiator system. The influence of DiAB content on the properties of the hydrogels was discussed. In the initial swelling stage, the swelling behavior of the four hydrogels changed from Fickian kinetics to non Fickian with increasing of molar fraction x(DiAB) from 0 to 3%. While x(DiAB) values were 0, 1%, 2% and 3%, the equilibrium swelling ratio SR0 of P(NIPA-co-DiAB) hydrogels were 63.6, 93.5, 141.6 and 167.4 in distilled water; 63.1, 71.0, 59.0 and 77.5 in a 0.01 mol/L SDS solution; 37.6, 42.2, 44.1 and 60.0 in a 0.01 mol/L CTAB solution; 30.9, 49.4, 68.5 and 88.3 in a 0.01 mol/L Triton X-100 solution respectively. It was found that the SR0 values of P(NIPA-co-DiAB) hydrogels were greater than that of PNIPA, and the SR0 values of the four hydrogels in distilled water were greater than those in 0.01 mol/L aqueous surfactant solution. The volume phase transition temperature or lower critical swelling temperature(LCST) of PNIPA hydrogel was enhanced from 32.5 ℃ in distilled water to 35.4 ℃, 45.6 ℃ or 80 ℃ in a 0.01 mol/L Triton X-100, CTAB or SDS solution, respectively. The LCST of P(NIPA-co-DiAB) hydrogels was increased from 32.0～32.5 ℃ in distilled water to 34.7～35.6 ℃, about 45.8~46.2 ℃ or 80 ℃ in a 0.01 mol/L Triton X-100, CTAB or SDS solution, respectively. It was shown that the LCST of P(NIPA-coDiAB) hydrogels was increased by adding surfactant. The high volume transition temperature was essentially independent of hydrophobic comonomer DiAB content.