One-step synthesis of Janus hydrogel via heterogeneous distribution of sodium α-linoleate driven by surfactant self-aggregation

Huowen Chen; Chuchu Zheng; Fusheng Zhang; Zhuqin Zhang; Lijuan Zhang

doi:10.1126/sciadv.adj3186

One-step synthesis of Janus hydrogel via heterogeneous distribution of sodium α-linoleate driven by surfactant self-aggregation

Sci Adv. 2023 Nov 10;9(45):eadj3186. doi: 10.1126/sciadv.adj3186. Epub 2023 Nov 8.

Authors

Huowen Chen¹, Chuchu Zheng¹, Fusheng Zhang¹, Zhuqin Zhang¹, Lijuan Zhang¹

Affiliation

¹ Guangdong Provincial Key Lab of Green Chemical Product Technology, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, P. R. China.

Abstract

Janus adhesive hydrogels have one-sided adhesive properties and hold promising applications in the health care field. However, a simple method for synthesizing Janus hydrogels is still lacking. In this study, we introduce an innovative method to prepare Janus hydrogels by harnessing a fundamental phenomenon: the self-aggregation of surfactants at high concentrations at the water-air interface. By combining a small amount [0.8 to 3.2 weight %, relative to mass of acrylamide (AM)] of sodium α-linoleate (LAS) with AM through free radical polymerization, we have synthesized Janus adhesive hydrogels. The Janus hydrogels exhibit remarkable adhesive strength and adhesive differences, with the top side (84 J m^-2) being 21 times stronger than the bottom side, also an excellent elongation rate. Through comprehensive experiments, including chemical composition, surface morphology, and molecular dynamics (MD) simulations, we thoroughly investigate the mechanisms of the hydrogel's heterogeneous adhesion. This study presents an easy, efficient, and innovative method for preparing one-sided adhesive hydrogels.