title: Unified scaling behavior of physical properties of clays in alcohol solutions.
abstract: This paper reports observation of universal scaling of physical properties of clay particles, Laponite (aspect ratio=30) (L) and Na Montmorillonite (MMT, aspect ratio=200), in aqueous alcohol solutions (methanol, ethanol and 1-propanol) with solvent polarity, defined through reaction field factor f(OH)(ɛ(0),n)=[(ɛ(0) - 1/ɛ(0) + 2) - (n(2) - 1/n(2) + 2)], at room temperature (20°C). Here, ɛ(0) and n are the static dielectric constant and refractive index of the solvent concerned. Physical properties (Z) such as zeta potential, effective aggregate size, viscosity and surface tension scaled with the relative solvent polarity as Z∼δf(α); δf=(f(w)(ɛ(0),n) - f(OH)(ɛ(0),n)), where f(w)(ɛ(0),n) is the reaction field factor for water, Z is the normalized physical property, and α is its characteristic scaling exponent. The value of this exponent was found to be invariant of aspect ratio of the clay but dependent on the solvent polarity only.
authors.affiliation: Nanomaterials and Nanocomposite Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110 067, India.
authors.forename: Ravi Kumar
authors.initials: RK
authors.lastname: Pujala
authors.forename: Nisha
authors.initials: N
authors.lastname: Pawar
authors.forename: H B
authors.initials: HB
authors.lastname: Bohidar