Development of Lignin Supramolecular Hydrogels with Mechanically Responsive and Self-Healing Properties

Abstract

The development of functional polymers from renewable lignin is attractive due to the depletion of fossil fuel and increasing environmental usage. A series of poly(ethylene glycol) methyl ether methacrylate (PEGMA)-grafted lignin hyperbranched copolymers were prepared by atom transfer radical polymerization (ATRP). The chemical structures, molecular characteristic and thermal properties of these copolymers were evaluated and such copolymers were prepared in a range of molecular weights from 38.7 to 65.0 kDa by adjusting the PEGMA-to-lignin weight ratio. As a result from their hyperbranch architecture, their aqueous solutions were found to form supramolecular hydrogels with a very low critical gelation concentration of 1 wt % copolymers, in the presence of α-cyclodextrin (α-CD). The rheological properties of the supramolecular assemblies were investigated and these hydrogel systems showed tunable mechanical response and excellent self-healing capability. Combined with good biocompatibility, these new types of green supramolecular hydrogels based on lignin−PEGMA/cyclodextrin inclusion are potentially useful as a smart biomaterial for biomedical application.

A Recent Perspective on Noncovalently Formed Polymeric Hydrogels

“…Our group studied shear‐thinning and self‐healing properties of supramolecular hydrogels with different types of polymeric entities ,. Dynamic rheological studies confirmed that non‐covalent inclusion complexation renders the sol‐gel process reversible subjected to shear and heating/cooling cycles.…”

Emerging Supramolecular Therapeutic Carriers Based on Host–Guest Interactions

“…Loh et al. furthermore prepared a series of PEGMA‐grafted lignin hyperbranched copolymers . The hyperbranched architecture formed supramolecular hydrogels with a very low critical gelation concentration of 1 wt % copolymers, in the presence of α‐CD (Figure ).…”

Polyhydroxyalkanoates: opening doors for a sustainable future

“…Depending on the carbon numbers in the monomeric constituents, PHAs can be classified as short-chain-length PHAs (C 3 -C 5 ), which consists of 3-5 carbon monomers, and mediumchain-length PHAs (MCL-PHA, C 6 -C 14 ), which consists of 6-14 carbon monomers in the 3-hydroxyalkanoate units (Figure 1b). 3,4 For example, poly(3-hydroxybutyrate) (PHB), poly(3-hydroxyvalerate) (PHV) and their copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are typical examples of short-chain-length PHAs, whereas poly(3-hydroxyoctanoate) (PHO) and poly(3-hydroxynonanoate) (PHN), which are primarily formed as copolymers with 3-hydroxyhexanoate (HHx), 3-hydroxyheptanoate (HH) and/or 3-hydroxydecanoate (HD), are typical examples of MCL-PHAs. More than 150 different PHA monomers have been identified, which renders them the largest group of natural polyesters.…”