Study on porous silk fibroin materials. II. Preparation and characteristics of spongy porous silk fibroin materials

Porous silk fibroin materials, with average pore size 10 ~ 300 μm, pore density 1 ~ 2000/mm², and porosity 35 ~ 70%, were prepared by freeze drying aqueous solution of silk fibroin obtained by dissolving silk fibroin in ternary solvent CaCl<INF>2</INF> · CH<INF>3</INF>CH<INF>2</INF>OH · H<INF>2</INF>O. Pore size distribution of such materials mostly accorded with logarithmic normal distribution. It is possible to control the aforementioned structural parameters and the physical properties of moisture permeability, compressibility, strength, elongation, etc., by adjusting freezing temperature and concentration of silk fibroin solution. Above glass transition zone (−34 ~ −20°C) of silk fibroin, the freezing temperature has more significant effect on the structure and properties of porous silk fibroin materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2192–2199, 2001