The Preparation And Properties Of Toughening Natural Biopolymer-based Hydrogels Assisted By Hofmeister Effect

Hydrogel has attracted the attention of the scientific community because of its high water content and three-dimensional network structure.Natural biopolymer hydrogels have been extensively studied in recent years due to their good biocompatibility.However,natural biopolymer hydrogels have poor mechanical properties and single properties,which cannot meet practical applications.The preparation of natural biopolymer-based hydrogels with excellent toughness and multiple properties is still a challenging problem.Therefore,it is of great significance to prepare a hydrogel with excellent mechanical properties and versatility.Herein,a natural biopolymer-based hydrogel is prepared using gelatin and carboxymethyl chitosan(CMCS)through a one-step soaking method.The prepared hydrogel without any synthetic polymers and crosslinking agents has a complete physical crosslinking structure.Due to the hydrophobic interaction brought by the Hofmeister effect,the mechanical properties of soaked hydrogels(tensile stress and strain can reach 3.77 MPa and 1082 %)are superior than traditional protein hydrogels.In addition,the prepared gelatin/carboxymethyl chitosan(Gel/CMCS)hydrogel exhibit a variety of properties,including good shape memory,fatigue resistance,electrical conductivity,water retention,drug releasing,antibacterial property,and recyclability.This strategy opens up a new horizon to manufacture hydrogels with excellent toughness and multiple functions,which can extend the application prospects in the biomedicine area and other related fields.Using sodium caseinate and gelatin as raw materials,a kind of natural protein-based hydrogel was prepared through Hofmeister effect caused by soaking in ammonium sulfate solution.The method of soaking overcomed the weakness of soft and fragile protein-based hydrogel.The test results showed that the hydrogel has excellent mechanical properties.The maximum tensile stress of hydrogel was 3.55 MPa,and the maximum tensile strain was 1375 %.The maximum conductivity of the hydrogel was 0.0954 S/m,and the conductivity sensitivity factor was 0.53.In addition,hydrogel also have good shape memory performance.This strategy opens up a new field of vision for the preparation of strong conductive hydrogels,and expands the application prospect of hydrogels in biomedical and electronic sensing fields.The strategy of realizing toughening of natural biopolymer-based hydrogels through this simple one-step immersion method will greatly broaden the application range of hydrogels.This research provides new insights for the development of a new generation of multifunctional hydrogels.