Malleable and Self-Healing Covalent Polymer Networks through Tunable Dynamic Boronic Ester Bonds

Abstract

Despite numerous strategies involving dynamic covalent bond exchange for dynamic and self-healing materials, it remains a challenge to be able to tune the malleability and self-healing properties of bulk materials through simple small molecule perturbations. Here we describe the use of tunable rates of boronic ester transesterification to tune the malleability and self-healing efficiencies of bulk materials. Specifically, we used two telechelic diboronic ester small molecules with variable transesterification kinetics to dynamically cross-link 1,2-diol-containing polymer backbones. The sample cross-linked with fast-exchanging diboronic ester showed enhanced malleability and accelerated healing compared to the slow-exchanging variant under the same conditions. Our report demonstrates the possibility of transferring small molecule kinetics to dynamic properties of bulk solid material and may serve as a guide for the rational design of tunable dynamic materials.

Transiently malleable multi-healable hydrogel nanocomposites based on responsive boronic acid copolymers

“…59,60 Recently, soft healable gels based on the reversible bonding of boronic acids with diols have also emerged in the form of multi-responsive polymer blends. [61][62][63][64] Inspired by these studies and our previous work on boronate ester constructs for chemical logic operations 65 and cell surface engineering, 66,67 we designed a simple boronic acidbased nanocomposite that exhibits complex, albeit predictable, physicochemical and mechanical behaviour as a multihealable model platform for cell encapsulation. Our proposed system comprises a synthetic thermoresponsive boronic acid copolymer that is crosslinked with poly(vinyl alcohol) (PVA) to form cytocompatible hydrogels within seconds under physiological conditions (Fig.…”

Chemical control of the viscoelastic properties of vinylogous urethane vitrimers

“…Currently, as recently reviewed by our group9, only a limited number of associative exchange chemistries101112131415161718192021222324 have been explored in the context of vitrimers, and one of the main challenges is the precise control of the exchange kinetics. Although Leibler and co-workers demonstrated that epoxy-based transesterification vitrimers can be controlled by changing catalysts8, the exchange reaction remains slow and high catalyst loadings and temperatures are required to enable processing in a reasonable timeframe678.…”

Adaptable Fast Relaxing Boronate‐Based Hydrogels for Probing Cell–Matrix Interactions

“…From a polymer physics perspective, the rate of stress relaxation, or the characteristic time scale of the viscoelastic properties, in a hydrogel is inherently dictated by the type of physically associative or reversible chemical bonds that create the network crosslinks 15, 16, 17, 18. In search of faster relaxation motifs, our investigation focused on dynamic boronate bonds, which started to gain attention in autonomous self‐healing materials,19, 20 functional bioconjugates,21 and complex chemical systems 22, 23.…”