Effects of Functionalization\non Photo-Actuatable Octa(dimethylsiloxy)silsesquioxane-Azobenzene\nNetwork Gels and their Substance Loading and Unloading Efficiencies

The synthesis, characterization, analysis, and effect\non solvent\nuptake of styrene, alcohol, amino, and perfluoro functionalized silsesquioxane-azobenzene\nhybrid gels are discussed. 4,4′-Diallyloxyazobenzene and octa(dimethylsiloxy)silsesquioxane\n(Q<sub>8</sub>M<sub>8</sub><sup>H</sup>) gels are generated using\nhydrosilylation chemistry. These gels were modified through two routes:\nin situ and postsynthesis modification, depending on the compatibility\nof the modifiers. The dynamic gel systems react to visible and UV\nlight to expand and contract, giving them sponge-like properties.\nThe general characteristics of each gel are illustrated through UV–vis,\nATR-FTIR, TGA, NMR, and SEM imaging. Effects on their solvent uptake\nload and preference for various solvents/pollutants are detailed below,\nand notable findings include preferences of the styrene material for\naromatics, perfluoro for THF, and alcohol for acetone. This is accompanied\nby a low affinity for water, enabling them to remove organic solvents\nand particulates from water. We find that selectivity for certain\nsubstances can be obtained but at the cost of the total absorptivity\nof the gel systems.