Fig. 1. Photolithographic patterning of gel and swelling-induced cooperative deformation.

(A) A precursor solution in the reaction cell was exposed to ultraiolet (UV) light irradiation through a mask to produce patterned gels in the light-exposed region. After the residual solution was removed (B), another precursor solution was injected into the interspace between the preformed gels (C). (D) Subsequent photopolymerization without a mask produced an integrated patterned gel. (E) After the periodic patterned gel was swollen in water, it deformed into an alternating concave-convex structure. Blue and red areas correspond to nonswelling and high-swelling gels, respectively. (F) Images of corresponding swollen patterned gel. Scale bars, 1 cm.