| 초록 |
The porous materials have been fabricated through complex processes such as electrochemical fabrication and lithography. An ideal fabrication has to be not only efficient but also adaptable enough to deal with a large number of dimensions. To overcome the limits of the conventional processes, a directional freezing can be considered. Here, ice crystals are used as a template to produce a porous film. A solvent is uni-directionally frozen and the pores after drying reflect the spaces occupied by the aligned crystals of solvents. SiO2, TiO2 nanoparticles and poly(vinylidene fluoride) (PVDF) were used to investigate the relationships between freezing kinetics and pore morphology. Using these materials, different freezing and annealing conditions were attempted to fabricate free-standing films with enhanced mechanical properties. Also, we discovered that directional solidification can make modifications of the crystal structures and physical properties, and improve mechanical properties. |
