Zhao Qian, Sun Jianzhong, Ling Qincai, Zhou Qiyun
State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China.
Langmuir. 2009 Mar 3;25(5):3249-54. doi: 10.1021/la8038939.
Macroporous thermosensitive poly(N-isopropylacrylamide) hydrogels were synthesized in the presence of dodecyl dimethyl benzyl ammonium bromide (DDBAB). Poly(vinyl alcohol) (PVA) was involved to control the pore size of the hydrogels. The morphology of the resulting hydrogels was studied by both an optical microscope and a scanning electron microscope. Moreover, the pore size and its distribution were examined by mercury intrusion porosimetry. The results indicated that size of the pores decreased with the increase of the amount of PVA added. The mechanism was explained after dynamic light scattering measurement of the size of hydrophobic initiator DDBAPS aggregates that were formed in situ in PVA aqueous solutions of various concentrations as the product of the reaction between DDBAB and the water soluble initiator ammonium persulfate. Swelling ratio and deswelling/reswelling kinetics of the hydrogels were also measured to investigate the response properties of the hydrogels. It would be a promising method of pore size control for synthesizing hydrogels of other vinyl monomers that could be initiated by persulfates.
在十二烷基二甲基苄基溴化铵（DDBAB）存在的情况下合成了大孔热敏性聚（N-异丙基丙烯酰胺）水凝胶。加入聚乙烯醇（PVA）以控制水凝胶的孔径。通过光学显微镜和扫描电子显微镜研究了所得水凝胶的形态。此外，通过压汞法测定了孔径及其分布。结果表明，随着PVA添加量的增加，孔径减小。通过动态光散射测量不同浓度PVA水溶液中原位形成的疏水引发剂DDBAPS聚集体的尺寸，解释了其机理，DDBAPS聚集体是DDBAB与水溶性引发剂过硫酸铵反应的产物。还测量了水凝胶的溶胀率和去溶胀/再溶胀动力学，以研究水凝胶的响应特性。这将是一种很有前景的孔径控制方法，可用于合成其他可由过硫酸盐引发的乙烯基单体水凝胶。
