Figure 2: Thermoresponsive behaviours of hydrogels.
(a,b) Pictures of a hydrogel prepared with IPAAm/TiNSs (10.0/0.4 wt%) at 25 and 40 °C in a test tube (a) and in a patterned PDMS matrix (b). (c) Transmittances (300 nm) of a 50-μm-thick film of the hydrogel at different temperatures in the range 20–40 °C, where the data with red filled circles and blue open squares are for the heating and cooling processes, respectively. (d) Time-dependent transmittance (300 nm) changes of a 50-μm-thick film sample of the hydrogel (blue curve) and those of a reference hydrogel (red curve) prepared with MBAAm as the crosslinker (IPAAm/MBAAm=10.0/0.1 wt%) in response to repeated temperature jump/drop cycles in the range 32–34 °C. (e) A three-dimensional microstructure of the hydrogel constructed with its sliced two-dimensional images, obtained at 34 °C by confocal fluorescence laser scanning microscopy, where the sample was doped with a fluorescent probe (8-anilino-1-naphthalenesulphonic acid ammonium salt). Scale bar, 10 μm. (f) Ion conductivities of the hydrogel at different temperatures in the range 23–38 °C at an applied cell voltage of 100 mV, where the sample was doped with LiClO4 (500 mM).
