Instituto de Fisica , Universidad Nacional Autónoma de México , P.O. Box 20-364, 01000 Mexico City , Mexico.
Instituto de Química , Universidad Nacional Autónoma de México , P.O. Box 70-213, 04510 Mexico City , Mexico.
J Phys Chem B. 2019 Nov 7;123(44):9481-9490. doi: 10.1021/acs.jpcb.9b07276. Epub 2019 Oct 24.
Chromophores susceptible to light-induced trans-cis isomerization embedded in cylindrical micelles can modify micelles and their light-responsive performance. A small chromophore (4-(phenylazo)benzoate ion) is embedded in cylindrical micelles made of cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) in water. The microstructure is examined by scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). Rheological behavior and the length scales of the micellar network are determined by rheology and microrheology. The chromophore substantially modifies the micelles even without UV irradiation. The larger is the chromophore concentration, the smaller is the micellar length. Additional length scales of the micellar network do not substantially vary even when NaCl is added. Chromophore incorporation also modifies the rheology of the micellar solution, although gradient shear banding is preserved. Viscosity decreases as the chromophore concentration increases, and viscoelastic spectra are modified, but when they are correctly rescaled, they can be superimposed. The addition of the chromophore makes the fluids more Maxwellian, particularly when NaCl is also added. When the chromophore is incorporated into the micelles, there is a response after UV irradiation, although it does not produce a significant rheological change.
发色团易发生光诱导顺反异构，嵌入在圆柱形胶束中，可以改变胶束及其光响应性能。小的发色团（对苯偶氮苯甲酸离子）嵌入在由溴化十六烷基三甲铵（CTAB）和水杨酸钠（NaSal）在水中形成的圆柱形胶束中。通过扫描电子显微镜（SEM）和核磁共振（NMR）来检查微结构。通过流变学和微流变学来确定流变行为和胶束网络的长度尺度。即使没有紫外线照射，发色团也会大大改变胶束。发色团浓度越大，胶束长度越小。即使添加 NaCl，胶束网络的其他长度尺度也不会有太大变化。发色团的掺入也会改变胶束溶液的流变性，尽管保留了梯度剪切带。随着发色团浓度的增加，粘度降低，粘弹性谱发生变化，但经过正确的缩放后，可以进行叠加。添加发色团会使流体更接近麦克斯韦尔流体，特别是当还添加 NaCl 时。当发色团掺入胶束中时，会在紫外线照射后产生响应，尽管它不会产生显著的流变变化。
