Schimka Selina, Lomadze Nino, Rabe Maren, Kopyshev Alexey, Lehmann Maren, von Klitzing Regine, Rumyantsev Artem M, Kramarenko Elena Yu, Santer Svetlana
Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany.
Institute of Chemistry, Technical University Berlin, 10623 Berlin, Germany.
Phys Chem Chem Phys. 2016 Dec 21;19(1):108-117. doi: 10.1039/c6cp04555c.
We report on light sensitive microgel particles that can change their volume reversibly in response to illumination with light of different wavelengths. To make the anionic microgels photosensitive we add surfactants with a positively charged polyamine head group and an azobenzene containing tail. Upon illumination, azobenzene undergoes a reversible photo-isomerization reaction from a trans- to a cis-state accompanied by a change in the hydrophobicity of the surfactant. Depending on the isomerization state, the surfactant molecules are either accommodated within the microgel (trans-state) resulting in its shrinkage or desorbed back into water (cis-isomer) letting the microgel swell. We have studied three surfactants differing in the number of amino groups, so that the number of charges of the surfactant head varies between 1 and 3. We have found experimentally and theoretically that the surfactant concentration needed for microgel compaction increases with decreasing number of charges of the head group. Utilization of polyamine azobenzene containing surfactants for the light triggered remote control of the microgel size opens up a possibility for applications of light responsive microgels as drug carriers in biology and medicine.
我们报道了一种对光敏感的微凝胶颗粒，它能够在不同波长光的照射下可逆地改变其体积。为了使阴离子微凝胶具有光敏感性，我们添加了具有带正电荷的多胺头部基团和含偶氮苯尾部的表面活性剂。光照时，偶氮苯会发生从反式到顺式状态的可逆光异构化反应，同时伴随着表面活性剂疏水性的变化。根据异构化状态，表面活性剂分子要么被容纳在微凝胶内部（反式状态）导致其收缩，要么解吸回到水中（顺式异构体）使微凝胶膨胀。我们研究了三种氨基数量不同的表面活性剂，这样表面活性剂头部的电荷数量在1到3之间变化。我们通过实验和理论发现，微凝胶压实所需的表面活性剂浓度随着头部基团电荷数量的减少而增加。利用含多胺偶氮苯的表面活性剂对微凝胶大小进行光触发远程控制，为光响应微凝胶作为生物和医学中的药物载体的应用开辟了可能性。
