Premium
Biasing Buckling Direction in Shape‐Programmable Hydrogel Sheets with Through‐Thickness Gradients
Author(s) -
Zhou Ying,
Duque Carlos M.,
Santangelo Christian D.,
Hayward Ryan C.
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201905273
Subject(s) - materials science , buckling , swelling , curvature , gaussian curvature , composite material , fabrication , gaussian , metric (unit) , geometry , mathematics , medicine , alternative medicine , physics , pathology , quantum mechanics , operations management , economics
A photocrosslinkable poly( N , N ′‐diethylacrylamide) copolymer allows for the photolithographic fabrication of hydrogel sheets with nonuniform crosslinking density and swelling ratio. Using this material system, different 3D shapes with nonzero Gaussian curvature K are successfully programmed by prescribing a “metric” defined by in‐plane variations in swelling. However, this methodology does not control the direction of buckling adopted by each positive K feature, and therefore cannot controllably select between different isometric shapes defined by a single metric. Here, by introducing gradients in swelling through the thickness of the gel sheet by tuning the absorption of the UV‐light used for crosslinking, a preferential buckling direction is locally specified for each feature by the direction of UV exposure. By also controlling the strength of coupling between neighboring features, this is shown to be an effective method to program buckling direction of each unit within a canonical corrugated surface shape.