Apparent molar volumes phi(v) and viscosity B-coefficients for nicotinamide in (0.00, 0.05, 0.10, and 0.15) mol . dm(-3) aqueous tetrabutylammoniurn bromide (TBAB) solutions have been determined from solution density and viscosity measurements at temperatures over the range (298.15 to 318.15) K as function of concentration of nicotinamide (NA). In the investigated temperature range, the relation: phi(V)degrees = a(0) + a(1)T + a(2)T(2), have been used to describe the temperature dependence of the standard partial molar volumes phi(V)degrees. These results have, in conjunction with the results obtained in pure water, been used to deduce the standard volumes of transfer Delta phi(V)degrees and viscosity Bcoefficients of transfer for nicotinamide from water to aqueous TBAB solutions for rationalizing various interactions in the ternary solutions. The structure making or breaking ability of nicotinamide has been discussed in terms of the sign of (delta 2 phi(V)degrees/delta T-2)(P). An increase in the transfer volume of nicotinamide with increasing TBAB concentration has been explained by Friedman-Krishnan co-sphere model. The activation parameters of viscous flow for the ternary solutions investigated were also determined and discussed by the application of transition state theory. (c) 2007 Elsevier Ltd. All rights reserved.