Reconfigurable and orthogonal stiffness-structure patterning of dynamically crosslinked amphigels

Patterning diversified properties and surface structure of polymer materials are of great importance toward their potential in biology, optics, and electronics. However, achieving both the patternability of stiffness and microstructure in a reconfigurable manner remains challenging. Here, we prepare amphigels crosslinked by dynamic disulfide bonds, which can be reversibly swollen by immiscible water or liquid paraffin. In the paraffingel form, the materials exhibited a high modulus of 130 MPa due to densified hydrogen bonds. Whereas swollen by water, the modulus fell over two orders of magnitude owing to the destruction of the hydrogen bonds. Via regionalized swelling of the solvents, well-controlled and rewritable soft/stiff mechanical patterns can be created. On the other hand, the dynamic exchange of the disulfide crosslinking enables mechanophoto patterning to fabricate sophisticated macrogeometries and microstructures. The reconfigurable stiffness-structure patterning can be manipulated orthogonally, which will create more application opportunities beyond conventional hydrogels and organogels. Stiffness and microstructure can be orthogonally patterned on the same amphigel. Through spatially selective swelling of immiscible liquid paraffin or water, reprogrammable soft/stiff mechanical patterns are created. With further photo-induced disulfide bond exchange of our network, sophisticated microstructures are independently constructed by mechanophoto patterning. Such a strategy employed by our amiphigel can inspire diverse novel applications beyond single hydrogel and organogel.image