Poly[2-methoxy-5-(2'-ethylbexyloxy)-p-phenylenevinylene](MEH-PPV)is a typical example of solution proeassable conjugated polymers for polymeric light emitting diodes application

which shows good solubility in conlnlon organic solvents．However

gelation or micro-gelation always occurs during the polymerization process．Herein

we report the synthesis of fully soluble MEH—PPV by ultrasonic irradiation method．The raw material was 4-methoxyphenol

and ultrasonic irradiation method was used in the etherification

bromomethylation and polymerization．The polymer is prepared from the bis—bromomethyl monomer through the Gilch route．Compared with the conventional mechanical stirring

ultrasonic irradiation method has shown great advantages with respect to the shorter reaction time

lower reaction temperature

higher yields and higher molecular eight(Mn)of MEH-PPV．The optimized reaction conditions including reaction solvent

temperature

and time

were determined for the related etherification

bromomethylation and polymerization with ultrasonic method．Especially

using ultrasonic method

the gelatification in the polymerization had been overcome．MEH—PPV obtained was fully soluble in THF and chloroform and no gel or micro—gel existed．The structures of the intermediate products and MEH-PPV were determined by IR and 1H—NMR．It was found the MEH—PPV synthesized by ultrasonic irradiation processes had higher luminescence quantum efficiency than that by mechanical stirring．