Design,Synthesis And Properties Of Optoelectronic Functional Viscoelastic Organic Materials

Viscoelastic organic materials are important functional soft substances in daily life.Further more,viscoelastic materials with optoelectronic functions have attracted widespread attention due to their optoelectronic properties and viscoelasticity.This class of material includes small molecules and polymers,both of which have ?-conjugated structures and are a new type of optoelectronic functional materials.In recent years,despite the rapid development of small molecules and polymers photoelectric viscoelastic materials,there are still some problems.For instance,(1)Small molecules are applied in many ways because of their color tunability,but the poor quality of luminous colors is often ignored.(2)Polymers become quite rigid due to their own ?-conjugated backbones.How to obtain viscoelasticity without destroying the conjugated structure is the first problem to be solved at present.(3)Compared with the single modulus of small molecules,how to regulate the moduli reasonably and efficiently to meet the application requirements of different moduli in life is also a challenge for polymers.To solve the problems above,a series of(phenylene)phenyl compounds with alkyl side chains are designed and synthesized in this subject,and corresponding solutions are proposed.We explored the structures and performance relationship of viscoelastic organic materials with optoelectronic functions.The main content of this topic includes three parts:(1)We designed and synthesized three small-molecule viscoelastic materials with bulky Guerbet-type alkyl side chains.The benzodithiazole,benzothiadiazole dithiophene,and thiophene were chosen as A(Accepter),DAD(Donor-Accepter-Donor),and D(Donor)type chromophores,which provide the expected luminescent color.Because the three smallmolecule viscoelastic materials all are liquids,we adopt liquid-liquid blending for the study of color controlling.Owing to viscoelasticity,any two or three materials are mutually miscible in any proportion.The blending color from such system is quite stable and uniform.This study shows that the blending of small-molecule viscoelastic materials with optoelectronic function can improve effectively the quality of luminous color,whose optoelectronic performance are extremely excellent.(2)We designed and synthesized three kinds of polymer viscoelastic materials with different ?-conjugated structure units.These polymers were softened without destroying the conjugated backbone by introducing bulky Guerbet-type alkyl side chains.These three types of polymer viscoelastic materials are subjected to stimuli-responsive color tuning,which is different from the small-molecules viscoelastic materials blending in the first part.The smallmolecules viscoelastic materials are homogeneous blending while the result of this part is microphase separation.(3)On the basis of the second part,we selected the red emitting polymer for its moduli tuning research.Meanwhile,a series of polymers based on benzothiadiazole dithiophene were designed and synthesized.Under the condition that keeping optoelectronic performance,the moduli tuning of the viscoelastic materials was achieved through the methods of adjusting the lengths of the alkyl side chain and blending the polymers.Unlike the second part,the polymers blending in this part can obtain a homogeneous and miscible mixture.What is more,the Arrhenius behavior was found,so corresponding blending ratio can be calculated according to the required moduli.This research shows that we can regulate the moduli of polymer viscoelastic materials with optoelectronic function as needed without destroying the optoelectronic characteristics.