Preparation And Photo-electrical Properties Of Poly(Phenylene Vinylene) Derivatives Substituented With Symmetrical Alkoxyl/Carbon Nanotubes Composites

In this paper,three types of poly(phenylenevinylene)derivatives with symmetrical and asymmetrical alkoxyl substituentes(ROPPV)were synthesized by dehydrochlorination process with p-methoxylphenol and p-diphenol as raw materials.These three types of polymers are:â‘ two kinds of PPV derivatives with symmetrical alkoxyl substituentes: poly(2,5-dibutoxy)phenylene vinylene(PDBOPV)and poly(2,5-dihexyloxy)phenylene vinylene(PDHOPV);â‘¡two systems of phenylene vinylene copolymer with alkoxyl substituted:(2,5- dihexyloxy)phenylene vinylene-co-(2-methoxy-5-butoxy)phenylene vinylene copolymer(P(HOPV-co-MOBOPV))and(2,5-dihexyloxy)phenylene vinylene-co-(2-methoxy- 5-octyloxy)phenylene vinylene copolymer(P(HOPV-co-MOCOPV));â‘¢poly(2,5-dibutoxy)phenylene vinylene/multi-walled carbon nanotubes(PDBOPV/MWCNTs).The molecular structure and luminescence properties of materials were characterized by FT-IR,Raman,~1H NMR,UV-Vis,XRD,TG,DSC,HRTEM,SEM,element analysis and photoluminescence sprctra.The relationship among structure,solubility,shape, stability and luminescene properties of PPVderivatives was studied.The experimental results indicates that the introduction of alkoxyl can greatly enhance the solubility of PPV in common organic solvents.The length of the side chain effects the properties of PPVderivatives,and the longer the side chain,the better the solubility,the lower the stability.Under the influence of alkoxy electron donating groups,the peak of photoluminescence and absorption spectra exhibits red-shift and this increase along with RO length.The space hindrance of alkoxy-substituented effects the polymerization of copolymer.And alkoxy-substituented is less space hindrance.So the more molar proportion of PPV derivatives prescursor with asymmetrical alkoxy-substituented,the better the copolymer polymerization.Doping PDBOPV with carbon nanotubes has been show to improve the chemical stability,thermal stability,solubility and luminescent properties of PDBOPV/MWCNTs composites.And it is formed the core-sheU structure which MWCNTs were coated by PDBOPV.The interation between MWCNTs and PDBOPV formed two effects:quantum size effect and charge transfer effect.Through common competition of two effects,the energy band gap of composite is changed,the peak of luminescence and absoption spectra shift.