Dynamic hydrogels are prepared by either dynamic covalent bonds or supramolecular chemistry. Herein, we develop a dynamic hydrogel by combining both dynamic covalent bonds and supramolecular chemistry that exhibits environmentally adaptive self-healing and pH-tuning properties. To do so, we prepared a gelatin–nanopolysaccharide mixed hydrogel containing pyrogallol/catechol groups and trivalent metal ions. The as-prepared hydrogels are able to heal damage inflicted on them under acidic (pH 3 and 6), neutral (pH 7), and basic (pH 9) environments. The mechanism of healing at acidic and neutral pHs is dominated by coordination bonds between pyrogallol/catechol groups of tannic acid and ferric ions, whilst…
High stretchability and mechanical stability are the key properties of a conductive polymer composite structure. In this work, an anisotropic composite is fabricated by wet 3D printing of epoxy crosslinked chitosan/carbon microtubes. The carbon microtubes were synthesized through a high temperature carbonization of chemically purified cellulose fibres. After the chemical treatment and high temperature carbonization, the removal amorphous substrates from the core of cotton fibres results in the formation of a tubular structure. Here, chitosan which is an abundant natural polymer was used as the composite matrix. It was found that the epoxy crosslinking increases the stretchability of composite filaments.
Over the last decays, the use of conductive biopolymer composites has been growing in areas such as biosensors, soft robotics, and wound dressing applications. They are generally soft hydrophilic materials with good elastic recovery and compatible with biological environments. However, their application and removal from the host are still challenging mainly due to poor mechanical strength. This work displays a technique for the fabrication of complex‐shaped conductive structures with improved mechanical strength by wet three‐dimensional (3‐D) printing, which uses a coagulation bath to quickly solidify an epoxy cross‐linked chitosan/carbon microtube composite ink. The fabricated conductive structure demonstrated higher elongation strength…