DETERMINATION OF MICELLAR HYDRODYNAMIC RADIUS BY REFRACTION

The technique of refractometry has been used to demonstrate the feasib ility of its application in the determination of the hydrodynamic radi us of micelles. The r(H) of dodecyl-beta-maltoside, beta-C-12-M, a non ionic sugar surfactant micelle has been calculated using refractive in dex values, n, obtained by refraction. The value of 34.8 +/- 0.02 Angs trom was found. This value is in excellent agreement with values obtai ned by other very sophisticated techniques. The r(H) and micellar volu me values obtained were insensitive to changes in concentration beyond the critical micelle concentration (c.m.c.) of this surfactant. The a pparent constancy of the r(H) values suggests the tight micelle format ion of the amphiphile.