Control superstructure of rigid polyelectrolytes in oppositely charged hydrogels via programmed internal stress

Abstract

Biomacromolecules usually form complex superstructures in natural biotissues, such as different alignments of collagen fibres in articular cartilages, for multifunctionalities. Inspired by nature, there are efforts towards developing multiscale ordered structures in hydrogels (recognized as one of the best candidates of soft biotissues). However, creating complex superstructures in gels are hardly realized because of the absence of effective approaches to control the localized molecular orientation. Here we introduce a method to create various superstructures of rigid polyanions in polycationic hydrogels. The control of localized orientation of rigid molecules, which are sensitive to the internal stress field of the gel, is achieved by tuning the swelling mismatch between masked and unmasked regions of the photolithographic patterned gel. Furthermore, we develop a double network structure to toughen the hydrogels with programmed superstructures, which deform reversibly under large strain. This work presents a promising pathway to develop superstructures in hydrogels and should shed light on designing biomimetic materials with intricate molecular alignments.

Switchable Materials Containing Polyzwitterion Moieties

“…4 buffer, 20 min (attached to surface) [65] HCl, dioxane 4 h, RT (attached to surface) [65] The hydrolysis was investigated on a silicone substrate coated with copolymers with 5-bicycloheptenyl triethoxysilane that provided a stable linkage through Si-O-Si bonds. The zwitterionic forms poly (21), poly (23), poly (25) and poly (27) were prepared by treatment of the modified surface with 0.1 NaOH for 20 min, while the hydrolysis of polycarboxybetaine esters poly (28) to zwitterionic polymer poly (29) was carried out in an acidic medium and proceeded within 4 h at ambient temperature.…”

“…Materials with the capacity to switch their properties can find a variety of applications, i.e., in biosensing, nanomedicine, tissue engineering and intelligent nanoelectronics and optics [1][2][3][4][5].…”

Polymer Adsorbed Bilayer Membranes Form Self-Healing Hydrogels with Tunable Superstructure

“…[5][6][7][8][9][10][11][12] For these potential use, the next challenge is to develop tough hydrogels with anisotropic super-structures of macroscopic scale, as like biological tissues. 13 A promising strategy is to incorporate self-assembled structures into hydrogels. The self-assembled structures, usually being more rigid and brittle than polymer networks, can rupture at loading and reform at unloading.…”

Regulating vesicle bilayer permeability and selectivity via stimuli-triggered polymersome-to-PICsome transition

“…Although both polyion complex (PIC) micelles [45][46][47] and PICsomes [29][30][31] are intrinsically sensitive to high ionic strength, pH, and temperature 40 , previous literature reports also hint, in a retrospective view, that the stability of PICs or interpolyelectrolyte complexes (IPECs) is highly dependent upon local concentrations and sequence arrangement of charged ionpairs 43,44,[48][49][50][51] . Sun et al 48 fabricated tough and viscoelastic polyamphoyte hydrogels via direct copolymerization of oppositely charged comonomers at >1.5 M total concentration in aqueous media containing 0.5 M NaCl.…”