Effect of pH, co-monomer content, and surfactant structure on the swelling behavior of microgel-azobenzene-containing surfactant complex
Effect of pH, co-monomer content, and surfactant structure on the swelling behavior of microgel-azobenzene-containing surfactant complex
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DOI：
10.1016/j.polymer.2014.10.027
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发表时间：
2014-12-01
期刊：
影响因子：
4.6
通讯作者：
Klitzing, Regine V.
中科院分区：
文献类型：
--
作者：
Richter, Marcel;Zakrevskyy, Yuriy;Klitzing, Regine V.
阴离子PNIPAM-co-AAA颗粒的收缩/溶胀转变可以通过使用与含偶氮苯的阳离子表面活性剂的相互作用的光来操纵。在这项研究中，pH缓冲液和它们的浓度，电荷密度（AAA含量）在微凝胶颗粒，以及上的微凝胶和表面活性剂之间的复合物形成的表面活性剂的间隔长度的影响进行了研究。结果表明，pH缓冲液的存在下，可以导致完全阻断这种复合物中的相互作用和所产生的微凝胶收缩/溶胀响应。缓冲离子和表面活性剂分子与微凝胶颗粒相互作用之间存在明显的竞争。当在具有固定浓度（电荷密度）的微凝胶的纯水溶液中工作时，颗粒的收缩/溶胀仅由微凝胶的表面活性剂和AAA基团的相对浓度（电荷比）控制。此外，对于较短的表面活性剂间隔物长度，颗粒收缩更有效。收缩过程的起始点不受表面活性剂疏水性的影响。这项工作为微凝胶颗粒和光敏表面活性剂之间的相互作用提供了新的见解，这在新的传感器系统中提供了很大的潜力。(C)2014爱思唯尔有限公司版权所有。
The contraction/swelling transition of anionic PNIPAM-co-AAA particles can be manipulated by light using interactions with cationic azobenzene-containing surfactant. In this study the influence of pH-buffers and their concentrations, the charge density (AAA content) in microgel particles as well as the spacer length of the surfactant on the complex formation between the microgel and surfactant is investigated. It is shown that the presence of pH buffer can lead to complete blocking of the interactions in such complexes and the resulting microgel contraction/swelling response. There is a clear competition between the buffer ions and the surfactant molecules interacting with microgel particles. When working in pure water solutions with fixed concentration (charge density) of microgel, the contraction/swelling of the particles is controlled only by relative concentration (charge ratio) of the surfactant and AAA groups of the microgel. Furthermore, the particle contraction is more efficient for shorter spacer length of the surfactant. The onset point of the contraction process is not affected by the surfactant hydrophobicity. This work provides new insight into the interaction between microgel particles and photo-sensitive surfactants, which offers high potential in new sensor systems. (C) 2014 Elsevier Ltd. All rights reserved.