Synthesis and light scattering study of hydroxypropyl cellulose microgels
Synthesis and light scattering study of hydroxypropyl cellulose microgels
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DOI：
10.1021/ma000776k
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发表时间：
2000-11-14
期刊：
影响因子：
5.5
通讯作者：
Gao, J
中科院分区：
文献类型：
--
作者：
Lu, XH;Hu, ZB;Gao, J
合成了热响应性羟丙基纤维素（HPC）微凝胶，并对其进行了表征。微凝胶颗粒通过在高于KPC的低临界溶液温度的基质表面活性剂（十二烷基三甲基溴化铵）分散体中化学交联塌陷的HPC聚合物链而获得。微凝胶颗粒的尺寸分布，通过动态光散射测量，已与合成条件，包括表面活性剂浓度，聚合物浓度，和反应温度。最终的微凝胶尺寸取决于HPC聚合物链之间的疏水相互作用和胶束间静电排斥之间的平衡。使用静态和动态光散射技术作为温度和交联剂浓度的函数，所得HPC微凝胶的溶胀和相变特性进行了分析。发现交联剂浓度的增加降低了收缩程度。稀释的HPC微凝胶颗粒（C <1.0 × 10（-5）g/mL）在室温和44 ℃（高于体积相变温度）下形成稳定的胶体分散体，这可能是由于空间效应。向水中添加食盐会降低HPC微凝胶的体积相变温度。
The thermally responsive hydroxypropyl cellulose (HPC) microgels have been synthesized and characterized. The microgel particles were obtained by chemically cross-linking collapsed HPC polymer chains in mater-surfactant (dodecyltrimethylammonium bromide) dispersion above the lower critical solution temperature of the KPC. The size distributions of microgel particles, measured by dynamic light scattering, have been correlated with synthesis conditions including surfactant concentration, polymer concentration, and reaction temperature. The final microgel size is determined by the balance between the hydrophobic interaction among HPC polymer chains and intermicelle electrostatic repulsion. The swelling and phase transition properties of resultant HPC microgels have been analyzed using both static and dynamic light scattering techniques as a function of temperature and cross-linker concentration. It is found that the increase in the cross-linker concentration reduces the shrinkage extent. The dilute HPC microgel particles (C < 1.0 x 10(-5) g/mL) form a stable colloidal dispersion at room temperature and at 44C (above the volume phase transition temperature), probably due to steric effects. Adding salt to water leads to a decrease of the volume phase transition temperature of HPC microgels.