Ionization Of Block Copolymer And Thermoelectric Properties Of?ANI?₄-b-PEO-b-?ANI?₄

Today,as energy is drying up,thermoelectric materials are expected to be highly renewable.There is a ubiquitous source of heat on Earth:from solar energy to industrial or vehicle exhaust,it can be converted to electricity using thermoelectric materials.Polyaniline?PANI?is one of the most common conductive polymers and has received considerable attention due to its ease of synthesis,high stability,controlled conductivity,and interesting redox properties.However,the solubility of polyaniline in organic solvents is low and the processability is poor,which restricts the practical application of polyaniline.While retaining the excellent properties of polyaniline,aniline oligomers increase the specific surface area due to their unique nanostructures,further increasing the reaction rate of polyaniline doping,redox,etc.,and thus are expected to be widely used in the field of thermoelectrics.application.In our previous studies,the aniline tetramer triblock copolymer has a clear molecular structure,a high Seebeck coefficient and good processability compared to polyaniline,but the conductivity is poor.PEDOT:PSS?CLEVIOS PH1000?is a highly conductive conductive polymer material.PEDOT itself is insoluble in most common solvents,while PESOT emulsified by PSS can be well dispersed in some polar solvents.CLEVIOS PH1000 is the best conductive PEDOT:PSS aqueous dispersion in the CLEVIOS series,which has excellent electrical conductivity,but its Seebeck coefficient is low,resulting in low power factor.This thesis attempts to ionize the aniline tetramer triblock copolymer and combine it with PEDOT:PSS to develop high performance organic thermoelectric polymer materials.The main research contents of this paper are as follows:?1?Using aniline dimer as raw material,aniline tetramer is synthesized by oxidative coupling method,and then reacted with dicarboxypolyethylene glycol?HOOC-PEO-COOH?to prepare triblock copolymer,then PEDOT:PSS It was blended with?ANI?₄-b-PEO₆₀₀-b-?ANI?₄ and cast into a film.The thermoelectric properties of the films with different composition ratios were studied,and the process was optimized to obtain the maximum power factor.The results show that the PEDOT:PSS component imparts high conductivity to the aniline block copolymer,and the ratio of PEDOT:PSS/?ANI?₄-b-PEO₆₀₀-b-?ANI?₄ composite film at room temperature is At 100:1,the treated conductivity is up to 32553 S/m,the Seebeck coefficient is 21.53?V/K;PEDOT:PSS and?ANI?₄-b-PEO₆₀₀-b-?ANI?₄.When the composite ratio of 4 is 100:20,the power factor of the composite film after treatment is the largest,being 14.61?W/?m·K²?,the conductivity is 30252S/m,and the Seebeck coefficient is 22.05?V/K.When the ratio of?ANI?₄-b-PEO₆₀₀-b-?ANI?₄ continues to increase,a PN transition occurs,from P-type to N-type,and the Seebeck coefficient is higher;when the ratio is 100:100 When it reaches-204.28?V/K,the overall power factor is reduced due to the sudden drop in conductivity,which limits the overall thermoelectric performance of the composite film.?2?The?ANI?₄-b-PEO₆₀₀-b-?ANI?₄,Li Cl and Na molecular sieves were used as raw materials,and the PEO in?ANI?₄-b-PEO₆₀₀-b-?ANI?₄ was blended.Ionization was carried out to investigate the thermoelectric properties of the triblock copolymer before and after ionization.The results show that the Seebeck coefficient of the triblock copolymer remains basically unchanged,up to 41.8?V/K after ionization;after the ionization,the Seebeck coefficient of the triblock copolymer increases with the increase of the ambient humidity.The absolute value of the triblock copolymer is changed from the P-type before ionization to the N-type after ionization,and the absolute value of the Seebeck coefficient after ionization is increased by two before ionization.The order of magnitude is-4322?V/K at79%RH,and the conductivity is 0.00102 S/m.?3?The ionized triblock copolymer was used as an additive,DMF was used as a solvent,and?ANI?₄-b-PEO₆₀₀-b-?ANI?₄ after ionization was blended with PEDOT:PSS,and then cast into a film.The thermoelectric properties of composite films of different proportions under different environmental humidity were studied,and the process was optimized to obtain the maximum power factor.The results show that with the increase of?ANI?₄-b-PEO₆₀₀-b-?ANI?₄-ion content,the contribution of the Seebeck coefficient to the power factor of the composite film offsets the negative impact of the decrease of conductivity.Therefore,the power factor of the composite film is continuously increasing.When the composite ratio is 100:25,the relative humidity is 79%,and the power factor of the composite film is up to 4.65?W/?m·K²?.At this time,the conductivity is 12346S/m,and the Seebeck coefficient is 19.37?V/K.