Bridge-rich and loop-less hydrogel networks through suppressed micellization of multiblock polyelectrolytes

Jihoon Han; Saeed Najafi; Youyoung Byun; Lester Geonzon; Seung-Hwan Oh; Jiwon Park; Jun Mo Koo; Jehan Kim; Taehun Chung; Im Kyung Han; Suhun Chae; Dong Woo Cho; Jinah Jang; Unyong Jeong; Glenn H Fredrickson; Soo-Hyung Choi; Koichi Mayumi; Eunji Lee; Joan-Emma Shea; Youn Soo Kim

doi:10.1038/s41467-024-50902-z

Bridge-rich and loop-less hydrogel networks through suppressed micellization of multiblock polyelectrolytes

Nat Commun. 2024 Aug 2;15(1):6553. doi: 10.1038/s41467-024-50902-z.

Authors

Jihoon Han^#¹, Saeed Najafi^#^{2

3}, Youyoung Byun⁴, Lester Geonzon⁵, Seung-Hwan Oh⁶, Jiwon Park⁴, Jun Mo Koo⁷, Jehan Kim⁸, Taehun Chung¹, Im Kyung Han¹, Suhun Chae⁹, Dong Woo Cho⁹, Jinah Jang⁹, Unyong Jeong¹, Glenn H Fredrickson^{3

10}, Soo-Hyung Choi⁶, Koichi Mayumi^{5

11}, Eunji Lee¹², Joan-Emma Shea^{13

14}, Youn Soo Kim¹⁵

Affiliations

¹ Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
² Department of Chemistry and Biochemistry, University of California, Santa Barbara, California, USA.
³ Materials Research Laboratory, University of California, Santa Barbara, California, USA.
⁴ School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea.
⁵ The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, Japan.
⁶ Department of Chemical Engineering, Hongik University, Seoul, Republic of Korea.
⁷ Department of Organic Materials Engineering, Chungnam National University, Daejeon, Republic of Korea.
⁸ Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
⁹ Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
¹⁰ Department of Chemical Engineering, University of California, Santa Barbara, California, USA.
¹¹ Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan.
¹² School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea. eunjilee@gist.ac.kr.
¹³ Department of Chemistry and Biochemistry, University of California, Santa Barbara, California, USA. shea@ucsb.edu.
¹⁴ Department of Physics, University of California, Santa Barbara, California, USA. shea@ucsb.edu.
¹⁵ Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea. ysookim@postech.ac.kr.

^# Contributed equally.

Abstract

Most triblock copolymer-based physical hydrogels form three-dimensional networks through micellar packing, and formation of polymer loops represents a topological defect that diminishes hydrogel elasticity. This effect can be mitigated by maximizing the fraction of elastically effective bridges in the hydrogel network. Herein, we report hydrogels constructed by complexing oppositely charged multiblock copolymers designed with a sequence pattern that maximizes the entropic and enthalpic penalty of micellization. These copolymers self-assemble into branched and bridge-rich network units (netmers), instead of forming sparsely interlinked micelles. We find that the storage modulus of the netmer-based hydrogel is 11.5 times higher than that of the micelle-based hydrogel. Complementary coarse grained molecular dynamics simulations reveal that in the netmer-based hydrogels, the numbers of charge-complexed nodes and mechanically reinforcing bridges increase substantially relative to micelle-based hydrogels.