Multifunctional polyurethane hydrogel based on a phenol–carbamate network and an Fe³⁺–polyphenol coordination bond toward NIR light triggered actuators and strain sensors

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....

A stretchable, environmentally stable, and mechanically robust nanocomposite polyurethane organohydrogel with anti-freezing, anti-dehydration, and electromagnetic shielding properties for strain sensors and magnetic actuators

“…44 It should be mentioned that the PANI and Fe 3 O 4 @TA particles could be recycled from the TAPU/Fe 3 O 4 @TA-PANI matrix due to the phenol-carbamate bond formed between TA and -NCO groups being thermally unstable. 26,45,46 As shown in Fig. 6c, the TAPU lm was completely dissolved aer being soaked in DMF solvent at 25 °C; in contrast, the TAPU/Fe 3 O 4 @TA-PANI-II lm still maintained the swelling state even at 80 °C for 2 h, which may be due to the fact that the introduction of Fe 3 O 4 @TA nanoparticles enhanced the cross-linking density of the TAPU/ Fe 3 O 4 @TA-PANI-II lm, as discussed before.…”

“…It should be mentioned that TA-based hydrophilic polyurethane (TAPU) was prepared by polymerization between IPDI, PPG, PEG (hydrophilic moiety), BDO, and TA (cross-linking agent) according to our previously reported method, but there were some modifications. 26 Then, TA-based magnetic polyurethane nanocomposites (TAPU/Fe 3 O 4 @TA) were fabricated based on the preparation procedure of TAPU except that Fe 3 O 4 @TA nanoparticles were introduced into the system in the pre-polymerization step. The TAPU/Fe 3 O 4 @TA nanocomposites containing 5, 10, and 15 wt% of Fe 3 O 4 @TA nanoparticles were denoted as TAPU/Fe 3 O 4 @TA-1, TAPU/Fe 3 O 4 @TA-2, and TAPU/Fe 3 O 4 @TA-3, respectively.…”

Remotely Controlled Light/Electric/Magnetic Multiresponsive Hydrogel for Fast Actuations

“…It also has attracted much attention owing to the fact that it does not require complex energy supply systems. Therefore, hydrogel actuators have been widely used in the fields of biosensors, 33 smart switches, 34 tissue engineering, 35 soft robots, 2 and so on.…”

Competition-Based Two-Dimensional Photonic Crystal Dually Cross-Linked Supramolecular Hydrogel for Colorimetric and Fluorescent Dual-Mode Sensing of Bisphenol A

“…9−11 The non-covalent interactions mainly include hydrogen bonds, 12 host−guest interactions, 13 and metal− ligand coordination. 14 supramolecular hydrogel construction owing to their propensity to encapsulate diverse guest molecules reversibly and selectively. Moreover, the formation of host−guest complexes can usually change the optical properties of the guest molecules significantly.…”

“…Dually cross-linked supramolecular hydrogels (DCSHs), which often contain both covalent and non-covalent linkers, are considered as advanced hydrogel materials for various applications . Compared with traditional polymer hydrogels, DCSHs show attractive advantages since covalent cross-linking serves to improve overall mechanical performance, while the non-covalent interactions endow the materials with good stimuli-responsiveness, dynamicity, reversibility, and toughness. − The non-covalent interactions mainly include hydrogen bonds, host–guest interactions, and metal–ligand coordination . Among them, the host–guest interactions based on β-cyclodextrins (β-CDs) are widely used in supramolecular hydrogel construction owing to their propensity to encapsulate diverse guest molecules reversibly and selectively.…”