A Chewing Gum Residue-Based Gel with Superior Mechanical Properties and Self-Healability for Flexible Wearable Sensor

Bioinspired Composite Materials with Amplified Clusteroluminescence: Chemodosimetric Interaction Targeting Hypochlorite in Aqueous Medium

Owing to the advantages of cellulose such as exceptional biocompatibility and biodegradability, we synthesized cellulose-grafted bisindolyl methane (BIM) (1. Cell) composite. This biobased smart material was used as an effective colorimetric and fluorescent sensor for hypochlorite in the aqueous medium with a detection limit of 0.02 μM. Interestingly, cellulose exhibited inherent clusteroluminescence in solution, which was further intensified by the probe acting as a dopant. Both the boronic acid and bisindole groups in probe 1 are essential for this enhanced fluorescence, as boronic acid enables boronate ester formation with cellulose, while the bisindole groups facilitate additional hydrogen bonding interactions. This unique dual functionality produces a strong, solution-phase clusteroluminescent effect, creating a rigid microenvironment that promotes long-range exciton migration and an amplified fluorescence response. Furthermore, the 1. Cell exhibited ∼2.8-fold quenching, while probe 1 alone exhibited negligible fluorescence change in the presence of hypochlorite. Mechanistic investigation reveals that the probe formed a boronate ester via the interaction with cellulose, which was subsequently cleaved in the presence of hypochlorite. The differences in the response might be attributed to the distinct nature of their self-assemblies; 1. Cell could form long-range highly ordered aggregates, while probe 1 alone in the aqueous medium resulted in spontaneous random aggregates. Additionally, we employed cellulose paper strips to explore the practicability of the probe as a paper-based sensor. The chemically modified paper strips, grafted with probe molecules, were found to be stable for a week and could effectively detect hypochlorite in the presence of interfering analytes via the naked eye and fluorescent color-changing response.

A Polyvinyl Alcohol-Tannic Acid Gel with Exceptional Mechanical Properties and Ultraviolet Resistance

Design and preparation of gels with excellent mechanical properties has garnered wide interest at present. In this paper, preparation of polyvinyl alcohol (PVA)-tannic acid (TA) gels with exceptional properties is documented. The crystallization zone and hydrogen bonding acted as physical crosslinkages fabricated by a combination of freeze-thaw treatment and a tannic acid compound. The effect of tannic acid on mechanical properties of prepared PVA-TA gels was investigated and analyzed. When the mass fraction of PVA was 20.0 wt% and soaking time was 12 h in tannic acid aqueous solution, tensile strength and the elongation at break of PVA-TA gel reached 5.97 MPa and 1450%, respectively. This PVA-TA gel was far superior to a pure 20.0 wt% PVA hydrogel treated only with the freeze-thaw process, as well as most previously reported PVA-TA gels. The toughness of a PVA-TA gel is about 14 times that of a pure PVA gel. In addition, transparent PVA-TA gels can effectively prevent ultraviolet-light-induced degradation. This study provides a novel strategy and reference for design and preparation of high-performance gels that are promising for practical application.