Biomimetic hydrophobic plastic foams with aligned channels for rapid oil absorption.

Although many oil absorption materials have been developed, it still remains a great challenge to achieve rapid absorption and efficient recovery. Over the past decade, research has focused on the development of freeze casting technology using water as a solvent. The materials prepared by this method have poor water resistance and are difficult to apply to oil absorption in aqueous environments. Here, an organic solvent freeze casting strategy is proposed to fabricate ultralight hydrophobic plastic foams with aligned channel structures. Through microscopy in situ observation, we revealed the growth morphology of ice crystals during directional freezing process. Moreover, aligned porous foams with various channel sizes are fabricated by regulating the cooling rate. We found that organic solvent-assisted freeze casting can enhance the hydrophobicity of the matrix material. These aligned porous foams exhibit excellent liquid absorption performance, with high absorption speed and large absorption capacity over a wide viscosity range. This approach has general applicability and can be used to tailor a wide variety of engineering plastic-based aligned porous foams, as long as they can dissolve in organic solvents.