A novel method to prepare water dispersible poly(benzimidazobenzophenanthroline) (BBL) by partial substitution of chain ends with poly(ethylene oxide)

Poly(benzimidazobenzophenanthroline) (BBL) was prepd. according to literature method and modified with poly(ethylene oxide) in a one pot synthesis. After pptn. in aq. sodium carbonate soln. and subsequent purifn., aq. dispersions were prepd. by ultrasonication. Particle sizes in the dispersions ranged from few tens of nanometers to several micrometers and most of the particles had sizes of 50-250 nm. Further studies indicated that the colloidal stability is a combined result of steric stabilization caused by excluded vol. interactions of PEO chains on particle surface and electrostatic stabilization by the dissocd. carboxylic acid groups on the particle surface. The product could be processed into uniform films 20-30 nm in thickness by spin coating onto gold-plated silicon substrates having aminethiol monolayer as the top most layer. [on SciFinder(R)]