The effects of temperature gradient on the behavior of liquids of hydrogen isotopes inside a spherical ICF target are theoretically investigated. Two models are developed. In the first model, only the effect of the surface tension gradient induced by a nonuniform external temperature field is considered. As a result, other temperature-induced effects, such as the mass transfer across the liquid–gas interface and the nonuniformity in the density, pressure, and viscosity of the fluids, are not included. The second model considers the additional effect created by the mass transfer, namely, the effect of condensation and evaporation. The net result in both cases is an expression for the temperature gradient at the target exterior which will sustain a uniform liquid layer of hydrogen isotopes inside a spherical ICF target.