Thermoresponsive ionogels with switchable adhesion in air and aqueous environments induced by LCST phase behavior

Abstract

The rapid development of wearable devices has an urgent demand for materials with switchable adhesion both in air and aqueous environments. Herein, we report a thermoresponsive ionogel with switchable adhesion...

A Wearable Glove with Electrothermal‐Controlled Ionogels for Adhesive Gripping

“…As an extension of the previous work, [ 33 ] butyl acrylate (BA), a widely used monomer to prepare commercialized adhesives, is used to construct the polymer network of the ionogel, which is prepared through a one‐step polymerization of the BA monomer in imidazolium ionic liquids (ILs) (1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][NTf 2 ]) using ethyleneglycol dimethacrylate (EGDMA) as a crosslinker and diethoxyacetophenone (DEOP) as a photo‐initiator.…”

“…Meanwhile, the interfacial adhesion is substantially weakened by the retraction of the butyl side chains and the excluded ILs. The excluded ILs act as a lubricant [ 35 ] to decrease the coefficients of friction on the ionogel surface [ 33 ] and play a vital role in weakening adhesion strength. To more sufficiently demonstrate the mechanism, ionic liquid was sprayed on the surface of ionogel at room temperature (25 °C), and the adhesion strength of ionogel against glass was measured (Figure S1, Supporting Information).…”

Preparation of tough and stiff ionogels via phase separation

“…As the temperature increased, the phase separation structure disappeared, and the IL and polymer re-mixed. 23 After heating and slow-cooling, the degree of phase separation intensified, resulting in a more pronounced structure. Conversely, the PAM 40 -IL([EBIM]Br) ionogel obtained through rapid-cooling displayed almost no visible phase separation structure under an optical microscope.…”

Ionic Liquids: An Ideal Solvent for Tuning the UCST Phase Behavior of Polymer Gels

“…The ionogels were fabricated through in situ photoinduced polymerization of acrylic acid (or acrylamide) in ILs using EGDMA and DEOP as the cross-linker and photoinitiator, respectively. , Figure a shows the structural formulas of the monomers, cross-linkers, and ILs used in this study. Imidazole cations with different side chain lengths and anions with different Lewis basicities were selected as ILs.…”