Versatility of the Preparation Method for Macroporous Cryogel Particles Utilizing the Inverse Leidenfrost Effect

We have investigated the versatility of a two-step preparation method, without a detergent, that combines both the inverse Leidenfrost effect and the cryogelation technique by using the macroporous particles of different kinds of monomers (four vinyl monomers) or a natural polymer (agarose). First, the precursor of polymers was dropped into liquid nitrogen to prepare the spherical frozen droplet by the inverse Leidenfrost effect. Second, the frozen droplets were cryo-polymerized at the frozen temperature; then, cryogel particles were prepared after thawing. Subsequently, the basic characteristics of the macroporous polymer particles obtained above were compared, focusing on the appearances, porous morphologies, and mechanical properties. It was found that the similar polymer particles could be obtained by the two-step preparation method, while there was a slight difference in their characteristics, depending on the type of monomers. Especially for the mechanical properties, the cryogel particles of the hydrophilic polymer exhibited a shape memory function with sponge-like elasticity, whereas the hydrophobic polymer particles were observed to be cracked after compression (i.e., no shape memory function). This work provides a versatile method of adopting various kinds of monomers and natural polymers for the preparation of macroporous particles. Hence, the method possibly has a potential to prepare and design tailor-made macroporous polymer particles for the application purpose.

Automated summary

This study investigates a two-step preparation method that combines the inverse Leidenfrost effect and cryogelation technique to prepare macroporous polymer particles. The method involves dropping polymer precursors into liquid nitrogen to create frozen droplets through the inverse Leidenfrost effect, followed by cryo-polymerizing the frozen droplets and preparing cryogel particles after thawing. The resulting macroporous polymer particles exhibit similar characteristics, with slight differences depending on the type of monomers used. The method has the potential to be used for the preparation and design of tailor-made macroporous polymer particles for various applications.