Biomimetic rigid cryogels with aligned micro-sized tubular structures prepared by conventional redox-induced cryopolymerization in a freezer

To adapt to nature, wood forms an oriented tubular porous structure that is feasible for transporting water and nutrition. Inspired from this adaptability, we here demonstrate a universal approach to obtain rigid cryogels of aligned micro-sized tubular structures by a redox-induced cryopolymerization conducted in a freezer. In contrast to the classical directional freezing method, our method free of any special instrument leads to the aligned porous structures that are dependent on gravity due to the tubular porous structures parallel to gravity direction regardless of the sample placement direction. The versatility of our method is proven in the fabrications of a series of cryogels varying different hydrophilicity. Among the resultant samples, the three-function crosslinked cryogenic sample containing carboxyl group (polyMAA-TRIM, 40/60) was tested to have an unprecedented property integrated by high mechanical strength (9.0 MPa of compressive moduli), good hydrophilicity, and efficient purification of lysozyme (purity > 90 %) from egg white solutions only driven by gravity.