Bilayer-folded lamellar mesophase induced by random polymer sequence

• Main Authors: Ahn, H. (Author), Kim, H. (Author), Lee, E. (Author), Park, G. (Author), Park, J. (Author), Seo, M. (Author), Shin, M. (Author), Yoon, D.K (Author)
• Format: Article
• Language: English
• Published: Nature Research 2022
• Online Access: View Fulltext in Publisher

 Randomness is perceived in two different extremes, in macroscopic homogeneity and local heterogeneity, but apparently far away from order. Here we show that a periodic order spontaneously arises from a binary random copolymer when self-assembly occurs in an ensemble containing > 1015 possible chain sequences. A Bernoullian distribution of hydrophilic and hydrophobic side chains grafted onto a linear backbone was constructed by random copolymerization. When the polymer chains associate in water, a sequence matching problem occurs because of the drastic heterogeneity in sequence: this is believed to generate local curvature mismatches which deviate from the ensemble-averaged interfacial curvature. Periodic folding of the self-assembled bilayer stabilizes the curvature instability as recurring hinges. Reminiscent of chain-folded lamellae found in polymer crystallization, this new liquid crystalline mesophase, characterized as bilayer-folded lamellae, manifests itself as an anisotropically alignable birefringent hydrogel with structural hierarchy across multiple length scales. © 2022, The Author(s).