Preparation And Response Of Zwitterionic Hydrogel

Hydrogel are soft,moist materials with three-dimensional polymer network that contain a large amount of water.It has good biocompatibility and have great potential in artificial organs,drug delivery,flexible sensing materials and tissue engineering.However,the mechanical strength and electrical conductivity of hydrogels cannot be recovered after dehydration,which seriously restricts the practical application of hydrogels.The irrecoverability of mechanical strength,conductivity and other properties after dehydration,has severely restricted the practical application of hydrogels.To address this issue,here we have carried out a series of experimental investigations,which are divided into the following parts:(1)In chapter 1,we reported a P(AA-SMA-SBMA)amphoteric copolymer based hydrogel,which is polymerized by acrylic acid(AA),octadecyl methacrylate(SMA)and dimethyl-(3-propyl sulfonate)ammonium hydroxide(SBMA).Due to the high strength of micelle crosslinking,the hydrogel has anti-swelling,high mechanical properties and reusability after dehydration.The structure of the original hydrogels and that after dehydration-hydration cycles were characterized by SEM、Raman、FT-IR、XRD、DSC、SAXS and rheology,etc.It was proved that the prepared hydrogels could maintain both the macroscopic properties and the micro-structures after several hydration/dehydration processes due to the synergistic effects of hydrophobic and super-hydrophilic interaction in the 3D networks structures.Moreover,the fabricated hydrogels possess high electronic sensitivity which could be used to monitor both junction motion and subtle movement like breathing and speaking.In addition,the sensitivity of hydrogel sensors maintains after several dehydration-hydration cycles.This work provides a type of hydrogels material with stable property after dehydration process by regulating hydrophobic and hydrophilic interaction,which is beneficial for the life-time of hydrogels devises.(2)In Chapter 2,we will use surfactants to control to control the anti-swelling,mechanical properties,reusability,electrical conductivity and sensing properties of P(AASMA-SBMA)hydrogel in the first chapter.In the experiment,nonionic surfactant,cationic surfactant and anionic surfactant were selected to explore.Infrared and Raman spectra show that the P(AA-SMA-SBMA)hydrogels prepared by the four surfactants in this paper contain hydrogen bond,hydrophobic interaction,electrostatic interaction and other main functional group characteristic peaks.But the mechanical properties,swelling property and ionic conductivity are different.The mechanical properties of surfactants improved the most when SDS was used.PASS hydrogels are more sensitive to salt concentration when ionic surfactants are used,and more sensitive to p H when non-ionic surfactants are used.The conductivity of ionic surfactent-PASS hydrogels is better than that of non-ionic surfactent-PASS hydrogels.An interesting non-ionic surfactant-PASS hydrogel(F127-PASS hydrogel)is also promising for sensor applications.On the other hand,due to the change of hydrophobic structure,the crystallinity,mechanical properties and anti-swelling properties of two kinds of nonionic surfactant hydrogels have changed,and F127-PASS hydrogel has no controllable rehydration ability.To sum up,the Tween 80-PASS hydrogel we designed in Chapter 1 has higher application potential in the field of flexible wearable sensors.