*2.2.3. Measurements of the oscillating behavior for poly(Vp-co-Ru(bpy)3) gels*

The gel membrane was cut into rectangles(side length, about 2 × 20 mm) and immersed into 8mL of an aqueous solution containing malonic acid (MA), sodium bromate (NaBrO3), and nitric acid (HNO3). Shape changes of the gel strip were observed and recorded using a microscope (OLYMPUS.IX71), and a video recorder (Victor Corp. SR-DVM700). The analysis was conducted by using the image processing software (Image J 1.38x). A one-pixel line along the length of recorded gel image was stored at regular time intervals (0.05 s). The stored pixel line images were sequentially lined up as a function of time by the computer. This image processing procedure constructs a spatio-temporal diagram. From the obtained diagram, the time-dependent change in the gel edge was traced for observing the behavior of the volume change.

## *2.3.1. Synthesis of the poly(AAm-co-AAC) gel*

The pH-responsive cylindrical hydrogels were prepared as follows. 0.533 g of acrylamide (AAm), 54.0 mg of acrylic acid (AAc), 12.8mg of N,N'-methylenebisacrylamide (MBAAm) as a cross-linker, and 22.6 mg of 2,2'-Azobis (2-methylpropionamidine) dihydrochloride as an initiator were dissolved in the O2 free pure water (3.0 mL). The gelation was carried out in glass tubes (internal diameters from 1.0 mm to 2.0 mm) at 50 °C for 21 h. After removing from their molds, the cylindrical gels were cut in pieces 3.0 mm long and hydrated in pure water.

The pH-responsive cylindrical microphase-separated gels were prepared as follows. The composition of monomers is same as the cylindrical hydrogels, and they were dissolved in the solutions of O2 free water/acetone mixtures (80/20, 70/30, 60/40, and 50/50 wt %). The polymerization was carried out in glass tubes (the size is same as above) at 50 °C for 21 h.

After removing from their molds, the cylindrical gels were also cut in pieces 3.0 mm long and hydrated in a graded series of methanol-water mixtures for 1 day each in 75, 50, 25, and 0 vol % methanol.

The pH-responsive microphase-separated tubular gel was prepared as follows. The composition of monomers is same as the cylindrical microphase-separated gels, and they were dissolved in the water/acetone mixture solution (70/30 wt %). The mold was made by coupling different size of glass tubes (external/internal diameters are 2.6/2.0, 1.0/0.6 mm), and the monomer solution was flowed into the tube-shaped space (external/internal diameters are 2.0/1.0 mm). The tubular gel was cut in pieces 4.0 cm long and hydrated in a graded series of methanol-water mixtures for 1 day each in 75, 50, 25, and 0 vol % methanol.
