Implementing continuous freeze-casting by separated control of thermal gradient and solidification rate

Abstract

Ice-templated porous materials from freeze-casting have attracted widespread attentions in many research fields. Several apparatuses based on the freeze-casting have been proposed to fabricate aligned porous materials, where the unidirectional growth of ice is mainly controlled by changing temperatures at the sample ends. The thermal conduction cross the whole sample restricts the freezing process in traditional freeze-casting methods. In this paper, a new approach of freeze-casting is proposed, where the thermal gradient and the solidification rate can be controlled independently for continuous directional freezing. The lateral thermal conduction provides an effective way to produce axially homogeneous porous structural materials with unrestricted length and controllable microstructures. Moreover, the axial homogeneity can also be further improved by adding a small amount of sucrose.