Effect of oxypropylene chain length on the surface properties of dialkyl glycerol ether nonionic surfactants

In this work, as a continuation of our studies concerning the preparation a nd surface properties of nonionic surfactants, derivatives of 1,3-dialkoxy- 2-propanols and 1,3-dialkoxy(oligooxypropylene)-2-propanols with oligooxypr opylene chains have been synthesized and investigated. The surface activity of these compounds has been determined, i.e., critical micelle concentrati on (CMC), surface excess concentration (Gamma), surface area demand per mol ecule (A), surface tension at CMC (gamma(CMC)), Delta G(ads)degrees, and De lta G(mic)degrees. A linear decrease of the log CMC vs number of oxypropyle ne groups is observed, and based on the Shinoda equation the work of cohesi on per oxypropylene group when passing from molecular to micellar state is calculated for 0.43 kT, The equivalent of CH2 in the aliphatic alcohol grou p its ca. 2.50 oxypropylene units. Surface properties of these surfactants, i.e., cloud point, wetting ability, contact angle, foam height, and emulsi on stability type (O/W), have been determined as well, (C) 1999 Academic Pr ess.