Figure 1.

Schematic illustration of the preparation process for hydrogels with a layered structure and oriented pores. (a) Sacran LC solution with a concentration of 0.5% w/v. (b) Film with layered structures, where sacran chains were oriented in-plane, formed by casting of (a). (c) Hydrogels having a layered structure formed by water immersion of (b) after thermal cross-linking at various temperatures, which are basis of subsequently produced layered hydrogels. (d) Frozen hydrogels keeping a layered structure of sacran chains surrounded by ice crystal. (e) Hydrogels having the layered structure and oriented pores formed by freeze drying and successive water immersion of (d). In (f), (d) was thawed and immersed in water to prepare nondried hydrogels for comparison to (e).