Advanced Functional Materials
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Stimuli-Responsive Materials: Light-Controlled Reversible Manipulation of Microgel Particle Size Using Azobenzene-Containing Surfactant (Adv. Funct. Mater. 23/2012)
As reported by Yuriy Zakrevskyy and co-workers on page 5000, all-optical reversible control of the swelling/contraction transition of a microgel is realized using an azobenzene-containing surfactant. The azobenzene unit is switched between the more hydrophobic trans (blue light) and the more hydrophilic cis (UV light) state, which alters the surfactant's affinity to the microgel. The trans-surfactant binds to the gel triggering its contraction and the cissurfactant unbinds leading to microgel swelling.