The Synthesis And Supermolecular Assembly Of PPV Derivate At The Air/Water Interface

Thanks to the unique optical and electrical properties caused by conjugated double bond,conjugated polymers can be widely used in phtoelectric device field. Therefore, the study of conjugated polymers 'structure and function, is definitely meaningful in both theoretical reseach and social production. In recent decades, researches in this field all over the world are very popular. The active layers of current optoelectronic devices are mainly fabricated by the methods of spin-coating or spraying. Although these methods can obtain uniform active layers, polymer chains are still in a disordered state of aggregation.This drawback results in no approach to supply relations between state of aggregation and photoelectric properties of conjugated Because of simple operation, lowcost, orderd arrangement at nano-and micron-sized, etc, Langmuir-Blodgett (LB) technique now becomes an effective approach in studying self-assembled molecular of conjugated polymers and relations between state of aggregation and photoelectric properties of conjugated polymers.We have successfully synthetized PPV derivatives containing long-chain alkoxy and azo groups,meanwhile we studied their monomolecular film by the method of assembled molecular on air-water interface according to LB technique. The main results are the following.(1) we have synthetized two kinds of PPV derivatives containing alkoxy and azo groups by means of witting and Gilch. IR and NMR spectra show that the product are the target product. TGA results show that these polymers synthetized here possess high thermal decompostion temperature (400℃) and good thermal stability. All the results show that the synthetic product meet the requirements of the thermal stability of optoelectronic devices.(2) We spread three kinds of PPVderivatives onto air-water interface.Results ofπ-A isotherm curves showed that these three kinds of polymers show good phase change with increasing of the surface pressure. Experiment of membrane stability showed that with the increasing of target pressure,the stability of monolayers went worse. Experiment of relaxation studied the single molecule behavior on the air-water interface.All the results showed that the MHPPV-alt-PPVderivative still has a strong viscoelasticity at the two-dimensional state such as the air/water interface.(3) We sucessfully transfer the monolayer to solid substrates by LB technique.UV and fluorescence characerization results showed in the process of preparation of multilayer LB films, molecular arrangement and orientation has not changed with the increasing number of layers. Meanwhile,MHPPV-alt-PPVderivative molecules were found gathered on the solid substrate in the form of H.(4) We explored photosensitiveness and electrocondctibility of PPV derivatives containing azo groups, which have laid the groundwork for future research.