This paper develops a new experimental/numerical technique for controlling phase interface motion, acceleration and temperature gradients during pure material solidification. The required time-dependent boundary conditions are predicted with an inverse numerical method, in order to produce the desired interfacial motion. The experimental study with freezing of water is performed in a rectangular test cell. Three cases of different interface accelerations are considered. It was observed that an accelerating interface required higher interfacial temperature gradients over time, while these gradients become nearly constant when the phase interface moves at a uniform velocity (zero acceleration). It is noted how the interfacial acceleration and temperature gradients affect the structural characteristics of the solidified microstructures. (C) 2004 Elsevier Ltd. All rights reserved.