Preparation And Properties Research Of Poly(Styrene-N,N-dimethylacrylamide)Nanosphere Hybrid Hydrogel

This paper chose a poly(styrene-N,N-dimethylacrylamide)(PS-co-PDMAA)nanosphere as a macromolecule microsphere,and introduce it into the polyacrylamide hydrophobic association hydrogel network,a conductive hydrogel with good mechanical toughness and rapid self-healing was prepared.The work includes the following two parts:The first part of the work prepared macromolecular nanospheres PS-co-PDMAA with hydrophobic polystyrene as the core and hydrophilic poly(N,N-dimethylacrylamide)as the shell by emulsion polymerization.After being introduced into the polyacrylamide(PAAm)hydrophobic association hydrogel network,multiple hydrogen bonds are formed between the PDMAA and PAAm molecular chains on the outer layer of the microspheres,so that the hydrogel has multiple hydrogen bonds and hydrophobic association double dynamic crosslinking.This gives the hydrogel good mechanical properties and fatigue resistance.The hydrogel toughness can reach 0.4 MJ/m3,the stress can be doubled,and after 10 cycles of stretching or compression,its mechanical properties and toughness have only slightly decreased.When the hydrogel is damaged,the multiple hydrogen bonds can make the hydrogel repair itself quickly,and the multiple hydrogen bonds help the hydrophobic chains re-associate and further improve the self-repair efficiency.At room temperature,the self-healing efficiency of 2 hours can reach 99%.In addition,the sodium ions and chloride ions contained in the hydrophobic association structure also give the hydrogel a higher conductivity(4S/m)and a highly sensitive strain sensitivity,so that the hydrogel can sensitively sense large or small strain signals(For example,finger bending or breathing).And after the hydrogel self-healed,the strain sensing ability of the hydrogel can also be restored quickly.The second part of the work is based on the above work,using glycerol to replace part of deionized water to prepare macromolecular microsphere hybrid hydrogel with antifreeze and moisturizing properties.The addition of glycerin will have an impact on the variousproperties of the original hydrogel.Therefore,this part of the research mainly prepared hydrogels with different compositions by changing the ratio of glycerin and water,and tested their mechanical properties,electrical conductivity and self-healing properties.The best dosage of glycerin is determined through the test results,so as to obtain a conductive hydrogel with good mechanical properties,excellent self-healing properties and excellent antifreeze.Therefore,this hydrogel is expected to become an ideal material for flexible sensors and will be widely used in the future.