*2.1.2. Measurement of Lower Critical Solution Temperature (LCST) for the Poly(VP-co-Ru(bpy)3) solution*

The lower critical solution temperature (LCST) of the polymer solution was measured under the reduced and oxidized states, by using Ce(SO4)2 as an oxidizing agent and Ce2(SO4)3 as a reducing agent, respectively. The polymer solutions (0.5 wt%) of poly(VP-*co*-Ru(bpy)3) were prepared by dissolving the polymer in a 0.3 M HNO3 aqueous solution and adding 5 mM Ce(SO4)2 or 5 mM Ce2(SO4)3, respectively. The LCST measurements were carried out with a spectrophotometer (JASCO, Model V-630) equipped with magnetic stirrers and a thermostatic controller. In this measurement, the 570 nm wavelength was used because it is the isosbestic point for the reduced and oxidized states of Ru(bpy)3. The transmittance (%) of the polymer solution at 570 nm was then recorded by raising the temperature at a rate of 0.5 °C/min.
