Microlenses Actuated by Hydrogels

Stimuli-responsive hydrogels can be used directly as microlenses and also serve as actuators for microlenses. Jiang s group used stimuli-responsive [Pg.164]

The authors demonstrated microlenses responsive to temperature and pH values, using respective responsive hydrogels a thermo-responsive hydrogel based on N-isopropylacrylamide (NlPAAm), and two pH-responsive hydrogels based on acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA), and 2-(dimethylamino)ethyl methacrylate (DMAEMA) and HEMA, respectively [27,28]. [Pg.166]

A set of microposts made of pH-responsive hydrogel was constructed in a microfluidic chamber. A circular aperture was formed in a flexible polymer slip. The sidewall and top side of the aperture were treated to be hydrophilic and hydrophobic, respectively. Again, since aqueous solutions remained only on hydrophilic pathways at pressures below a critical value, part of the water-based liquid attached to the sidewall could form a liquid meniscus protruding downward at low pressures and upward at high pressures. [Pg.167]

2 Microlenses Actuated through Nanoparticle-Incorporated Hydrogels [Pg.167]

Focal length of pH-responsive liquid microlens using AA hydrogel as function of pH. (Source Dong, L., A.K. Agarwal, D.J. Beebe et al. 2006. Nature, 442(7102), 551-554. With permission.) [Pg.168]

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