Surface hydrophobization of hydrogels via interface dynamics-induced network reconfiguration

• Published in: Nature communications Vol. 15; no. 1; p. 239
• Main Authors: Yi, Bo, Li, Tianjie, Yang, Boguang, Chen, Sirong, Zhao, Jianyang, Zhao, Pengchao, Zhang, Kunyu, Wang, Yi, Wang, Zuankai, Bian, Liming
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.01.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 140/146; 147/3; 639/301/923/1027; 639/301/923/1028; 639/638/298/923/1027; Chains (polymeric); Chemical composition; Drug delivery; Grafting; Humanities and Social Sciences; Hydrogels; Hydrophobicity; Molds; Molecular dynamics; multidisciplinary; Polymers; Reconfiguration; Science; Science (multidisciplinary); Skin; Substrates; Surface properties; Wettability
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-44646-5

Effective and easy regulation of hydrogel surface properties without changing the overall chemical composition is important for their diverse applications but remains challenging to achieve. We report a generalizable strategy to reconfigure hydrogel surface networks based on hydrogel–substrate interface dynamics for manipulation of hydrogel surface wettability and bioadhesion. We show that the grafting of hydrophobic yet flexible polymeric chains on mold substrates can significantly elevate the content of hydrophobic polymer backbones and reduce the presence of polar groups in hydrogel surface networks, thereby transforming the otherwise hydrophilic hydrogel surface into a hydrophobic surface. Experimental results show that the grafted highly dynamic hydrophobic chains achieved with optimal grafting density, chain length, and chain structure are critical for such substantial hydrogel surface network reconfiguration. Molecular dynamics simulations further reveal the atomistic details of the hydrogel network reconfiguration induced by the dynamic interface interactions. The hydrogels prepared using our strategy show substantially enhanced bioadhesion and transdermal delivery compared with the hydrogels of the same chemical composition but fabricated via the conventional method. Our findings provide important insights into the dynamic hydrogel–substrate interactions and are instrumental to the preparation of hydrogels with custom surface properties. It is useful to be able to control the surface properties of a hydrogel, but tuning the surface without altering bulk properties of the hydrogel is challenging. Here, the authors report a method for modifying the surface of a hydrogel by grafting of polymer chains to the mold.