Study On Preparation And Properties Of Supramolecular Conductive Gels Based On Pillararene-Containing Polymers

In recent years,new energy has become the theme of development in China,giving birth to a series of new energy industrial chains.Therefore,higher requirements are put forward for the storage and utilization of electric energy.In order to meet the different needs of electrolytes,energy storage devices,sensors and other fields,the new generation of conductive materials has become a hot topic.Conductive gels have become the leading role in the field of soft electronics because it combines the three-dimensional micro/nano structure of gel with the electrical properties of semiconductor,and the porous structure of gel makes ions and molecules easy to diffuse.However,the traditional way of preparing conductive gel is cumbersome.Supramolecular chemistry can construct gel by means of non-covalent bond,which is a simple and easy way.It not only makes gel dynamic and adjustable,but also has high strength and good stability.Pillararene,as the new star of the host macrocycle,has the characteristics of symmetrical structure,easy functionalization,and complexation with a variety of guest molecules.In this paper,pillararene-containing homopolymer,block and random copolymers can be obtained by ring-opening metathesis cyclopolymerization（ROMP）or metathesis cyclopolymerization（MCP）.Guest molecules were further added to construct supramolecular conductive gel.The contents are as follows.The ionic liquid monomer（[Mlz NM⁺][TFSI^-]）with polymerizable group was synthesized.The block copolymer p MPHMB₂₅-b-p Mlz NM₂₅and the random copolymer p(MPHMB₂₅-co-Mlz NM₂₅)were obtained by ROMP as guest molecules.The two guest molecules were introduced into pillararene-containing homopolymers to construct supramolecular conductive gels.The ionic conductivity of supramolcular gel could be tuned by adjusting the molar ratio of host and guest molecules.At the same time,with the same content of the host molecule,the conductivity of the systems were different due to the different regularity of the guest molecules,which showed that the conductivity of p MPHMB₂₅-b-p Mlz NM₂₅was better than p(MPHMB₂₅-co-Mlz NM₂₅).However,the glass transition temperature of the system was too high,which led to poor conductivity.In order to improve the performance of conductive gel,the following improvements were made.Pillararene-containing block copolymers p NMP5A₁₀-b-p DYP5A₄₀and p NMP5A₄₀-b-p DYP5A₁₀as well as random copolymer p(NMP5A₄₀-co-DYP5A₁₀)were obtained by ROMP-MCP chain polymerization.Then two bifunctional ionic liquids were complexed with pillararene-containing polymers to construct supramolecular gels with tunable conductivity.As the molar ratio of polyacetylene segments in the polymer increased,the electrical conductivity increased.Increasing the content of guest molecules in the system could also improve the conductivity.Through comparative experiments,it was found that the conductivity of supramolecular gels prepared by bifunctional[PEG₁₀₀₀-（Py）₂]²⁺[TFSI^-]₂ionic liquid was higher than that of[PEG₄₀₀-（Py）₂]²⁺[TFSI^-]₂.In addition,adding lithium salt into the system made the conductivity of the system increase first and then decrease.Due to the addition of guest molecules,the glass transition temperature of the system dropped sharply,leading to the improvement of conductivity.