Preparation And Properties Of Tetraphenylethene-containing Thermotropic Liquid Crystals Based On Biomolecules

The order and fluidity of liquid crystal assembly structure are the important basis for living systems to perform specific functions and play an important role in living organisms.Biological macromolecules,such as nucleic acid and protein,tend to exist in solid state in solvent-free condition,and will decompose under heating condition,which makes them difficult to form liquid crystal materials with good fluidity.Solvent-free biomolecules-based thermotropic liquid crystal materials are new developed biomaterials,which are composed of DNA,polypeptides,sugars and other biomacromolecules with surfactants.Currently,solvent-free biomolecular thermotropic liquid crystal materials have been reported.Due to the simple structure of the surfactant used,the mechanical properties are poor,and it is difficult to show its specific functions in in-situ monitoring,tracer related applications because it does not have fluorescence properties.There fore,it is of great value to design and synthesize solvent-free biomolecular thermotropic liquid crystal materials with good mechanical properties and convenient detection.Traditional fluorescent materials are affected by aggregation induced quenching effect,which is difficult to give fluorescent property in the state of aggregated solid state.In contrast,aggregation induced emmison（AIE）materials reach the maximum fluorescent emission in the aggregation state,which expands the application range of fluorescent materials.Tetraphenylethene（TPE）is a typical AIE material.The biomolecules-based thermotropic liquid crystals obtained by combining TPE surfactant with biomolecules can exhibit fluorescence in solvent-free condition.In this study,we designed and synthesized a kind of ammonium surfactants TPEA.TPEA at room temperature has obvious aggregation induced luminescence property.After static complexation with DNA,the resulted DNA materials present nematic thermotropic liquid crystal material phase,and has good thermal stability,the stability of liquid crystal and fluorescence properties.Cellulose liquid crystal materials and lignin liquid crystal materials with fluorescent properties and waterproof properties can be prepared by electrostatic complexation between TPEA and sodium carboxymethyl cellulose/sodium lignosulfonate.In conclusion,by combining TPEA with biomacromolecules,a variety of biomacromolecule thermotropic liquid crystal materials with excellent mechanical properties and fluorescence properties are successfully obtained.Via screening the stoichiometric charge ratio between CMC-Na and TPEA,a catalyst-loading material with large surface area,rich catalyst loading sites,waterproof,excellent fluorescence performance,is developed.Gold nanoparticles are loaded into CMC-TPEA material,which solves the problem that gold nanoparticles are easy to agglomerate,difficult to recycle.The characterization data show that the catalyst has good thermal stability,waterproof,recyclability and fluorescent properties.