title: Free Energy of Scission for Sodium Laureth-1-Sulfate Wormlike Micelles.
abstract: Wormlike micelles (WLMs) are nanoscale, self-assembled components of many products from shampoos to fracking fluids due to their viscoelasticity. Their rheological behavior is largely governed by the contour length of the micelles and the concomitant propensity of the micelles to overlap and entangle. The large contour lengths, on the order of micrometers, is the result of a delicate balance between the scission enthalpy of the wormlike micelles on the one hand and entropic factors such as the mixing entropy of dispersion, the ordering of water molecules and counterions, and the mobility of branch points on the other hand. The structure and contour length of wormlike micelles assembled from sodium laureth-1-sulfate was determined at various temperatures using small-angle neutron scattering. The results allow the calculation of the enthalpy and entropy as well as the free energy of scission and are employed to critically evaluate the common methods to determine micellar scission energy from mean-field theory. Interesting behavior is observed when comparing branched and unbranched WLMs that may reflect on mechanistic differences in chain scission.
authors.affiliation: Biomedical, Chemical, and Environmental Engineering, University of Cincinnati , Cincinnati, Ohio 45221, United States.
authors.forename: Karsten
authors.identifier: 0000-0003-3206-1070
authors.initials: K
authors.lastname: Vogtt
authors.affiliation: Biomedical, Chemical, and Environmental Engineering, University of Cincinnati , Cincinnati, Ohio 45221, United States.
authors.forename: Hanqiu
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Biomedical, Chemical, and Environmental Engineering, University of Cincinnati , Cincinnati, Ohio 45221, United States.
authors.forename: Gregory
authors.initials: G
authors.lastname: Beaucage
authors.affiliation: P&G Analytical Sciences, 8700 Mason-Montgomery Road, Mason, Ohio 45040, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Weaver