CROSS-PHENOMENOLOGICAL COEFFICIENTS .11. NONLINEAR TRANSPORT EQUATIONS

An improved technique for the experimental measurement of electroosmotic pressure and streaming potentials involving pressure differences of the order of a few centimeters of pressure has been described. Measurements on electroosmotic velocity and electroosmotic pressure are reported for higher magnitudes of pressure and potential differences, ΔP and respectively, for Pyrex-acetone systems. Data on electroosmotic flow JΔP=0 obey the equation JΔP=0 = L12(Δφ/T) + 1/2L122(Δφ/T)2, whereas the data for net flow Jtotal due to both ΔP and Δφ are found to satisfy the nonlinear transport equation J = L11(ΔP/T) + L12( Δφ/T) + L112(ΔPΔφ/T2) + 1/9L122(Δφ/T)2 + 1/2L1112(ΔP)2· Δφ/T3 + 1/2L1112[ΔP(Δφ)2/T3], where L11, L12, L122, L1112, and L1122 are constants.