Hydrogen‐bonded supramolecular polymers as self‐healing hydrogels: Effect of a bulky adamantyl substituent in the ureido‐pyrimidinone monomer

Abstract

In an attempt to generate supramolecular assemblies able to function as self-healing hydrogels, a novel ureidopyrimidinone (UPy) monomer, 2-(N 0 -methacryloyloxyethylureido)-6-(1-adamantyl)-4[1H]-pyrimidinone, was synthesized and then copolymerized with N,N-dimethylacrylamide at four different feed compositions, using a solution of lithium chloride in N,N-dimethylacetamide as the polymerization medium. The assembling process in the resulting copolymers is based on crosslinking through the reversible quadruple hydrogen bonding between side-chain UPy modules. The adamantyl substituent was introduced in order to create a "hydrophobic pocket" that may protect the hydrogen bonds against the disruptive effect of water molecules. Upon hydration to equilibrium, all copolymers generated typical hydrogels when their concentration in the hydrated system was at least 15%. The small-deformation rheometry showed that all hydrated copolymers were hydrogels that maintained a solid-like behavior, and that their extrusion through a syringe needle did not affect significantly this behavior, suggesting a self-healing capacity in these materials. An application as injectable substitutes for the eye's vitreous humor was proposed. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39932.

Linear shear and nonlinear extensional rheology of unentangled supramolecular side-chain polymers

“…Supramolecular polymers based on UPy groups have been widely investigated and materials with important characteristics such as stimuli-responsive [23], self-healing [10,11,[49][50][51][52] and temperature responsive [53,54] properties have found applications within printing [55][56][57][58], cosmetics [59,60], adhesives [61] and coatings [62]. As an example of how supramolecular associations can play an important role, for inkjet printing applications a UPy-modified polyether mixed with stabilizers, antioxidants and colourants was used in work by Jaeger et al [55].…”

Synthesis and Biomedical Applications of Self-healing Hydrogels

“…The polyvinyl alcohol-based self-healing hydrogels were developed using the freezing/thawing method via hydrogen bonding (Zhang et al, 2012 ; Zhang, Z. et al, 2017 ). Moreover, hydrogen bonding-based self-healing hydrogels were frequently reported with incorporations of various chemical moieties, such as 2-ureido-4-pyrimidone (UPy) moieties (Cui and del Campo, 2012 ; Dankers et al, 2012 ; Cui et al, 2013 ; Bastings et al, 2014 ; Chirila et al, 2014 ; Hou et al, 2015 ; Zhang et al, 2016 ), nucleobase moieties (Ye et al, 2017 ), deferoxamine moieties (Xu et al, 2017 ), and gallol moieties (Shin and Lee, 2017 ). In a recent work, the cytosine- and guanosine-modified hyaluronic acid (HA) formed self-healing hydrogel by Watson-Crick base pairing between the nucleobases through hydrogen bonding (Ye et al, 2017 ).…”

Self-healable mussel-mimetic nanocomposite hydrogel based on catechol-containing polyaspartamide and graphene oxide

“…Hydrogels can be further classified as chemical hydrogels or physical hydrogels, according to whether covalent bonding or noncovalent interactions form their three-dimensional polymeric networks, respectively. Recently, some significant research has been focused on physical hydrogels; the noncovalent bonds in physical hydrogels can include hydrogen bonds, hydrophobic interactions, metal-ligand coordination bonding, or guest-host interactions [1][2][3][4][5][6][7]. These physical hydrogels can easily respond to the external environment, including stimuli such as temperature, pH, and light, and can have self-healing properties [8][9][10].…”