3D Printing Of Tough Hydrogels With Programmable Deformation Structure

Since hydrogels have good biocompatibility,hydrogels have great application prospects in tissue engineering,intelligent materials,biomedical fields and so on.With the development of macromolecule science and the need of practical application,a large number of studies focus on tough smart hydrogels.However,the structures obtained by traditional manufacturing methods are mostly block and thin film structures,which are simple in shape and deformation,slow in response,and difficult to meet the practical application requirements.The emergence and development of 3D printing provides a new manufacturing method for hydrogels.In this work,3D printing and finite element analysis methods of tough hydrogels with programmable deformation ware explored.The work has four aspects:selection and preparation of tough hydrogels,the method about 3D printing of tough hydrogels with programmable deformation structure,finite element analysis of hydrogels' large deformation,and the development of a new 3D printing fluid feeding device.In the first part,the preparation and curing process of traditional hydrogel precursor poly(acrylic acid-co-acrylamide)(P(AAc-co-AAm))solution and salt-sensitive hydrogel precursor poly(acrylic acid-co-N-isopropylacrylamide)(P(AAc-co-NIPAm)solution were introduced.Then,the printing and bonding properties of these two hydrogels were investigated,and a 3D printing method to improve the bonding properties of the two materials was proposed.The deformation of printing structure was controlled by designing the 3D printing path.we also printed a "gripper" structure to prove the excellent mechanical properties of the deformable structure through measuring the output force of the "gripper".The second part mainly explored how to use finite element analysis to simulate the large deformation of hydrogels.Here,three thermosensitive hydrogel structures with complex deformation were numerically simulated and analyzed.The analysis results were highly consistent with the experimental results,which provided a method for the numerical simulation of hydrogels' large deformation.The third part mainly introduced a new method to construct a new type of liquid feeding device.This new device could improve the printability of high viscoelastic hydrogels and solve the swelling of hydrogels during extrusion.The device is based on the Weissenberg effect that the hydrogel solution can flow out along the rotating needle.The feeding method can effectively avoid the problem of extrusion swelling and is also applicable to high viscoelastic hydrogels.As a result,we can improve the printing accuracy and enlarge the printable range of the hydrogels.We have explored the whole 3D printing process of the tough hydrogels with programmable deformation structure.Also,we provided a finite element analysis method to analysis the hydrogels's large programmable deformation that could be used to forecast,verify,analysis and guide the designing of experiment At last,we constructed a new fluid feeding deviece that suitable for hydrogel solutions to improve the printing accuracy.The manufacturing and finite element analysis method of hydrogels' programmable deformation structure were systematically explored in this paper.