Continuous ice-templating of macro-porous materials with uniformly ordered architecture

Abstract

Ice-templating technique offers a viable means for constructing ordered macro-porous architectures in materials; nevertheless, it is generally limited by a low efficiency for fabrication, large difficulty for manipulation, along with the small dimension, and poor structural uniformity of ice-templated materials. Here, a new approach was exploited for continuous ice-templating of uniformly ordered macro-porous materials based on the establishment of a large, stable temperature gradient with specific bi-directional designs at the freezing front by descending the front toward the cooling medium to accommodate its upward growth. The freezing rate was markedly increased with the dimension of frozen body notably enlarged as compared with the case for conventional static ice-templating technique. The macro-porous architecture of materials, taking zirconia ceramics as an example, was made much finer and more uniform over the entire sample, and exhibited better ordering of alignment and enhanced inter-connectivity between lamellae. This led to an improvement in the compressive strength and its stability along the height direction for ice-templated materials than those made by the static ice-templating technique at a similar porosity. This study may facilitate the scale up of ice-templating techniques and promote the exploitation and application of new high-performance materials. [Figure not available: see fulltext.]