Synthesis and Volume Phase Transition of Poly(methacrylic acid-co-N-isopropylacrylamide) Microgel Particles in Water
Synthesis and Volume Phase Transition of Poly(methacrylic acid-co-N-isopropylacrylamide) Microgel Particles in Water
复制标题
DOI：
10.1021/jp972990p
复制
发表时间：
1998-02
影响因子：
3.3
通讯作者：
Shuiqin Zhou;B. Chu
中科院分区：
文献类型：
--
作者：
Shuiqin Zhou;B. Chu
以甲基丙烯酸（MAA）和N-异丙基丙烯酰胺（NIPAM）为原料，在pH = 3.1 ± 0.2，温度70 °C的水溶液中合成了一系列轻度交联、近单分散、无规共聚的微凝胶粒子。聚合动力学、胶体稳定性和微凝胶颗粒的尺寸随共聚单体组成而变化。采用激光光散射法（LLS）研究了不同PMAA含量的MAA/NIPAM共聚物微凝胶颗粒在极稀水溶液（C< 1 × 10- 5g/mL）中的体积相变，在25 °C时，体积相变随pH值的变化，在pH值为3.4和7.5时，体积相变随温度的变化。据我们所知，这种亚微米尺寸的水凝胶的体积相变敏感的多种环境变化进行了研究，第一次由LLS。平衡溶胀比，临界转变pH值，和临界转变温度（Tc）强烈依赖于共聚单体。
A series of lightly cross-linked, nearly monodisperse, and random copolymerized microgel particles, based on methacrylic acid (MAA) and N-isopropylacrylamide (NIPAM) of various content, were synthesized in aqueous solution with sodium dodecyl sulfate at pH = 3.1 ± 0.2 and 70 °C. The polymerization kinetics, the colloidal stability, and the size of the microgel particles varied with the comonomer composition. The volume phase transitions of the MAA/NIPAM copolymer microgel particles with different PMAA contents in very dilute aqueous solution (C< 1 × 10-5 g/mL) were investigated by laser light scattering (LLS), as a function of both pH at 25 °C, and temperature at two different pH values of 3.4 and 7.5. To our knowledge, the volume phase transition of such submicron-sized hydrogels sensitive to multiple environmental changes was studied for the first time by LLS. The equilibrium swelling ratio, the critical transition pH, and the critical transition temperature (Tc) were strongly dependent on the comonomer...