Multifunctional polyurethane hydrogel based on a phenol–carbamate network and an Fe3+–polyphenol coordination bond toward NIR light triggered actuators and strain sensors. Issue 32 (5th August 2022)

• Record Type: Journal Article
• Authors: Liu, Yang; Zhang, Zetian; Liang, Ze; Yong, Yong; Yang, Changkai; Li, Zhengjun
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 32(2022)
• Page Start: 16928
• Page End: 16940
• Publication Date: 2022-08-05
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta04837j
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A novel polyurethane hydrogel based on a phenol–carbamate network and an Fe 3+ –polyphenol coordinative network was designed to be used as an NIR light triggered actuator and strain sensor. Abstract : Multifunctional smart hydrogels have been extensively used in wearable devices, soft robotics, tissue engineering, and information storage, especially those with good mechanical properties, desired stimuli-responsiveness, high strain sensitivity, and recyclability. Herein, a novel synergistic dual-network polyurethane hydrogel was prepared through two steps, that is, tannic acid (TA) was firstly incorporated into a polyurethane backbone comprising thermosensitive polyethylene glycol/polypropylene glycol (PEG/PPG) blocks to obtain TA-based polyurethane (TAPU) bearing a phenol–carbamate network; subsequently, TAPU film was immersed in FeCl3 aqueous solution to obtain a TAPU/Fe hydrogel bearing an Fe 3+ –polyphenol network. The prepared TAPU/Fe hydrogel exhibited a high tensile strength of 0.75 MPa, and large elongation at break of 550%. Benefiting from the thermosensitivity of PEG/PPG blocks and the photothermal effect of the Fe 3+ /TA complex, the TAPU/Fe hydrogel showed ideal near-infrared (NIR) light triggered actuating behavior and photothermal stability. Under the irradiation of NIR light, the flower-shaped hydrogel actuator can bend upward vertical to the horizontal plane within 2 min. Furthermore, Fe 3+ incorporated into the hydrogel matrix can endow the TAPU/Fe hydrogel sensor with high strain sensitivity, which can be used for real-time, stable and repeated monitoring of human movement, and can also be designed as a light-driven switch to light an LED bulb. Built on the reversible cross-linked networks, the TAPU/Fe hydrogel with good biocompatibility can be recycled. Unexpectedly, the TAPU hydrogel showed blue fluorescence under UV light (365 nm) irradiation, and the fluorescence could be quenched (with Cu 2+ ) and recovered (with ethylenediaminetetraacetic acid), resembling rewritable papers.