Construction Of High Conductivity/High Strength Lithium-Salt Elastomers And Application To Paper-Based Conductive Materials

With the continuous deepening of research on wearable medical devices,electronic skin,artificial muscles,etc.,the rapid development of flexible electronics research has been promoted.As one of the key materials for flexible electronics,soft materials such as hydrogels and ionic gels have been applied on a large scale,but hydrogels and ionic gels suffer from water evaporation and ionic liquid leakage,respectively.In order to fundamentally solve the above problems,the development of stretchable materials based on all-solid-state ionic conductors has become a new research trend.However,most all-solid-state ionic conductor materials suffer from low electrical conductivity(<10^-2 S/m),poor mechanical properties（stress strength<5MPa,tensile strain<1000%）,relatively low transparency and the presence of organic solvents in the preparation process.May pollute the environment and other issues.Polymerizable Deep Eutectic Solvents（PDES）has the characteristics of negligible vapor pressure,ionic conductivity,stable thermodynamic properties and chemical stability,low cost,simple manufacturing process,less post-treatment,and biodegradation.The characteristics can well avoid the water limitation of the hydrogel performance and solve the problem of ionic liquid leakage in the ionic gel from the root.Therefore,in this thesis,starting from Lithium-salt type Polymerizable Deep Eutectic Solvents monomer（Li-PDESs monomer）using the strategy of polymerizable eutectic,a series of high ionic conductivity and transparency were prepared through rational design.All-solid-state Lithium-Salt Elastomers（LSEs）with high self-healing efficiency.In view of the generally low strength and toughness of the current stretchable ionic conductors,xylan polymer was introduced as the second network to prepare a high-strength and high-toughness all-solid-state double-network lithium salt elastomer.The prepared high strength and high-toughness all-solid-state double-network lithium salt elastomer is combined with paper to prepare high-strength and high-toughness ion conductive paper.The specific research contents are as follows:（1）Based on the polymerizable deep eutectic strategy and the structural advantages of the integration of Li-PDESs monomer,lithium bis（trifluoromethanesulfonate）imide（Li TFSI）was chosen as the hydrogen bond acceptor and acrylic acid（AA）and maleic acid（MA）as the hydrogen bond donor to prepare Li-PDES monomer₁ of Li TFSI-AA and Li TFSI-MA type Li-PDES monomer₂.By adjusting the ratio of the two Li-PDES monomers,four Li-PDES monomers₃ were obtained,and highly conductive all-solid lithium salt elastomers were obtained by UV photopolymerization.One of the LSEs exhibited a high ionic conductivity（1.43 S/m）,together with good optical properties（92.10%transmittance）and excellent mechanical self-healing efficiency（up to 91.02%at 70°C for 48 h）.The LSE was used in a motion detection sensor and the LSE showed good detection results.（2）In view of the generally low strength and toughness of existing all-solid ionic conductors,DNLSE with high strength and high toughness were prepared by introducing a double network structure design.xylan was combined with Li-PDES monomer of Li TFSI-AA type to produce DNLSE with high strength and high toughness by taking advantage of the molecular structure of xylan’s polyhydroxyl group and the double network structure of the system.One of the DNLSEs has a tensile strain of 2604%,a stress strength of 10.38 MPa and a toughness of 156.02MJ×M^-3.The elastomer is also puncture resistant and can successfully lift 10 kg（10,000 times its own weight）,demonstrating good mechanical properties.The next step was to combine it with 3D printing to print 3D devices with good interlayer structure,broadening the range of applications for DNLSE.（3）Based on the characteristics of Li-PDESs monomer,a conductive ink was prepared by adding rhodamine B to four Li TFSI-AA-xylan type Li-PDESs monomer,and the paper was immersed in the conductive ink for one minute and finally photopolymerized in situ to prepare a high strength and high tenacity double network ionic conductive-paper(Double The paper was immersed in conductive ink for one minute and then photopolymerized in situ to produce a high strength and high tenacity Double Network Ionic Conductive-Paper（DNIC-Paper）.This ionic conductive paper has improved mechanical properties compared to the original paper,with a strength of approximately 26.63 MPa,a 2.05 times increase in strength,and a toughness of approximately 352.77 MJ×M^-3,a 3.30 times increase in toughness.