The critical micelle concentration(CMC) value and surface charge of the amphiphilic graft copolymer PECA-g-PEG micelles(PECA:polyethyl cyanoacrylae, PEG:polyethylene glycol) are reported. CMC of the copolymers is determined from the absorbance change of bromophenol blue solution as function of copolymer concentration, which is about 1×10 -6 mol/L. The critical coagulation concentration (cz c) of electrolytes with different valence(z) for the copolymer micelles are examined by visual method and compared with that obtained by experiential formula cz c∝z -6. The relation formula for different cations is deduced:cz c∝z -4, which indicates the electronegative character of the micelle surface.
Amphithatic polymeric microparticles were prepared from copolymers of poly(alkyl cyanoacrylate)(PACA) and poly(ethylene glycol)(PEG)(PACA co PEG) by evaporation method. And drug loaded copolymeric microparticles were formed by mixing polymeric microparticles with paracetamol(PCTM) as a simulated drug. The polymeric microparticles are round shaped with outer diameter <200 nm as determined by dynamic light scattering and transmission electron microscopy. The degradation rate of PECA co PEG was less than that of homopolymer PECA; while degradation rate of PECA was larger than that of PBCA(PECA:polyethyl cyanoacrylate; PBCA:poly butyl cyanoacrylate).
