Fig. 5
From: Adjacent cationic–aromatic sequences yield strong electrostatic adhesion of hydrogels in seawater
Universality of the strategy. a Chemical structures of other cationic and aromatic monomers, including ATAC, (3-acrylamidopropyl)trimethyl ammonium chloride (APTC), PEA, 2-(phenylsulfanyl)ethyl acrylate (PSEA), 2-(2-phenoxyethoxy)ethyl acrylate (PDEA), and benzyl acrylate (BZA). b Stress–strain curves of various poly(cation-adj-π) hydrogels. All the samples were prepared at equimolar ratio and with a 0.1-mol% chemical crosslinker. All the gels were equilibrated in 0.7 M NaCl solutions before the tests, and the initial strain rate was 0.14 s−1. c Adhesion values of various poly(cation-adj-π) hydrogels. The error bars indicate standard deviation (n = 5). The applied normal pressure was 100% of the elastic modulus of the gels for all the tests. All the tests were performed on a glass substrate in a 0.7 M NaCl solution
