Polymerizable deep eutectic solvent-gels synthesized in situ under molecular engineering control exhibit excellent
Changhang Zhang1, Xiaoyu Li1, Xinyu Wu1
1Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China; Jiangsu Engineering Research Center of Fast-growing Trees and Agri-fiber Materials, Nanjing, Jiangsu 210037, China.
Abstract:
Hydrogels generally do not adhere well to different substrates and freeze at sub-zero temperatures, limiting their application. In this study, the strategy of replacing water in hydrogels with deep eutectic solvents (DES) was used to address these challenges. Specifically, choline chloride (ChCl) as hydrogen bond acceptor, acrylic acid (AA) and itaconic acid (IA) as hydrogen bond donors and polymerizable monomers constitute PDES. Afterwards, PDES-gel (PG) was obtained by adding a thermal initiator to polymerize AA and IA in PDES. PG has the following characteristics, because PG is almost water-free, it has remarkable low-temperature tolerance without any phase change at -60 °C to 20 °C. Thanks to the carboxyl groups and chloride ions contained in PG, it can form non-covalent interactions such as hydrogen bonding and ionic interactions with different substrates, so PG can adhere to various substrate surfaces. Furthermore, the breaking elongation of the novelty PG was up to ca. 960 %, tensile strength ca. 1 MPa, outstanding transparency with an average light transmittance of about 95 % in the visible-light range. Ultimately, the novel PG exhibited certain capabilities for moisture detection and deformation sensing. The new PDES-gel material developed using PDES is expected to provide new ideas for the advancement of wearable devices.
