An organogel based on multiple dynamic covalent chemistry can respond to pH, redox and glucose, as well as self-heal quickly.
Inorganic-organic co-assembly of anionic polyoxometalates (POMs) with zwitterions provides a facile way to fabricate functional soft materials. In this paper, a translucent, photoluminescent polymer hydrogel was fabricated from Weakley-type POM Na9EuW10O36 (EuW10) and polymerizable imidazole-type zwitterion 3-(1-vinyl-3-imidazolio)propanesulfonate (VIPS) via a one-step synthesis method. Detailed characterization indicated that the polymerization of double bonds in VIPS and electrostatic interactions between EuW10 and VIPS play important roles in the formation of the hydrogels. Additionally, the introduction of non-polymerizable zwitterions 3-(1-methyl-3-imidazolio)propanesulfonate (MIPS) or 3-(1-decyl-3-imidazolio)propanesulfonate (C10IPS) can improve the mechanical and luminous performances of the hydrogels. Especially, C10IPS with a long alkyl chain would more significantly alter the coordination environment of EuW10, and consequently resulted in a more efficient energy transfer process. Further investigations revealed that the chemical environment around the Eu3+ can be highly influenced by organic solvents with stronger coordination abilities than water molecules, such as acetone. The translucency and luminescence intensity of the hydrogels can be reversibly transformed after alternately immersing in acetone or H2O for several minutes. Our results provided a useful strategy for the fabrication of luminescent hydrogels by regulating the noncovalent interactions between POMs and zwitterions.
Single-tailed and gemini-type supra-gelators were facilely fabricated via the conjugation of the d- or l-enantiomeric dihydrazide TDH with single-tailed achiral aldehyde C12BAD through dynamic acylhydrazone bonding. Chirality transfer from small molecules to supramolecules was successfully achieved via the spontaneous assembly of the formed supra-gelators into supramolecular chiral hydrogels.
Organogels can repair the damage rapidly, and the relative xerogels can adsorb methylene blue with high efficiency.
Biocompatible antibacterial hydrogels as novel dressing materials have been a widely researched method in modern medical technology. Here, we designed and prepared a new type of multifunctional antibacterial hydrogels that used poly(vinyl alcohol) (PVA)-tetrahydroxyborate anion (B(OH)4−) hydrogel as a vector and pyrrolidinium ionic liquids (ILs) as antibacterial drugs. The formation of borate ester bonds between PVA and B(OH)4− as dynamic network junctions endows hydrogels with multiple functions. Moreover, the as-prepared hydrogel exhibited effective anti-microbial activity against Escherichia coli and Staphylococcus aureus. Our results indicated that the hydrogels containing ILs with longer alkyl chain exhibited more pronounced antibacterial properties. The moisture retention, self-healing, syringeability and multiresponse behavior together with the antibacterial properties of the hydrogels make them ideal candidates as multifunctional dressing materials for joint skin wound healing.
表面活性剂是依靠分子间的弱相互作用实现自组装的,包括疏水相互作用、氢键作用力、主客体相互作用、静电相互作用、π-π堆积相互作用、金属配位相互作用和电荷转移相互作用等.通过调节分子间的相互作用可以实现对两亲分子自组装的调控,本文介绍了弱相互作用对两亲分子自组装形成有序分子聚集体结构和功能的影响.
We report a new strategy for fabricating a smart low molecular weight hydrogel based on dynamic covalent chemistry from a bola-type supra-gelator, which was facilely fabricated in situ from two non-assembling building blocks, (3-(2-(4-formylphenoxy) ethyl)-1-methyl imidazolium bromide, MA) and (3,3-dithiobis (propionohydrazide), DSPDZ), through dynamic acylhydrazone bonding. The obtained low molecular weight hydrogels exhibited redox-responsive and controllable self-healing properties. The role of dynamic covalent bonding in the formation of smart hydrogels is revealed in this study, which provides a simple and bottom-up method for constructing smart low molecular weight hydrogels.