Preparation of thermosensitive submicrometer gel particles with anionic and cationic charges
Preparation of thermosensitive submicrometer gel particles with anionic and cationic charges
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DOI：
10.1021/la9811867
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发表时间：
1999-06-08
期刊：
影响因子：
3.9
通讯作者：
Kokufuta, E
中科院分区：
文献类型：
--
作者：
Ito, S;Ogawa, K;Kokufuta, E
以N-异丙基丙烯酰胺（NIPA）、N，N′-亚甲基双丙烯酰胺（Bis）、丙烯酸（AAc）或1-乙烯咪唑（VI）为单体溶液，研究了表面活性剂水溶液氧化还原聚合法制备亚微米级聚电解质凝胶颗粒。以十二烷基苯磺酸钠和过硫酸铵分别作为表面活性剂和引发剂。用光子相关光谱对透析纯化的凝胶颗粒进行了表征。由于单体溶液中AAc和VI的含量控制在0 ~ 30 mol %范围内，在25℃下，羧基或咪唑基转化为相应的盐态时，AAc或VI含量为30 mol %的凝胶颗粒直径从125 nm增加到600 nm。然而，从阴离子或阳离子凝胶颗粒中完全消除电荷会产生中性凝胶，其尺寸从25℃时的125 nm（膨胀状态）到50 nm（完全崩溃状态）不等。这些膨胀行为与nipa基离子体凝胶相同。用电位滴定法和电泳光散射法对含有30 mol % AAc的凝胶颗粒进行了详细的检查，发现凝胶前溶液中几乎所有的COOH基团都被纳入颗粒内部，而颗粒表面没有浓度。
Aqueous redox polymerization using a surfactant was studied to prepare submicrometer-sized polyelectrolyte gel particles from a monomer solution containing N-isopropylacrylamide (NIPA), N,N'-methylenebisacrylamide (Bis), and acrylic acid (AAc) or 1-vinylimidazole (VI). Sodium dodecylbenzene-sulfonate and ammonium persulfate were used as the surfactant and the initiator, respectively. The gel particles purified via dialysis were characterized by photon correlation spectroscopy. Since the AAc and VI contents of the monomer solutions were controllable within 0-30 mol %, the diameter of the gel particles with 30 mol % of AAc or VI increased from 125 to 600 nm at 25 degrees C when converting the carboxyl or imidazolyl groups into the corresponding salt form. However, a complete elimination of charges from the anionic or cationic gel particles gave rise to a neutral gel, the size of which varied from 125 nm at 25 degrees C (swollen state) to 50 nm at temperatures > 35 degrees C (fully collapsed state). These swelling behaviors were the same as those of NIPA-based ionic bulk gels. Detailed examinations of the gel particles with 30 mol % AAc by potentiometric titration and electrophoretic light scattering shamed that almost all of the COOH groups in the pregel solution were incorporated into the particle interiors without concentration on the particle surface.