instability then was created by decreasing the gas pressure to ambient pressure this lead to the nucleation and growth of co 2 pores within the polymer matrices the nacl particles subsequently were removed from the matrices by leaching the matrices in distilled water for 48 hours all processing steps were performed at ambient temperature scaffolds were circular disks with a diameter of about 12 mm and a thickness of about 3 mm the pore size range was controlled by using nacl particles with a diameter of about 250 425 u03bcm in the processing the total porosity of scaffolds was calculated using the known density of the solid polymer the measured polymer mass of the scaffold and the measured external volume of the scaffold in this example the scaffolds are characterized incubation of nacl crystals in 95 humidity resulted in fusion of the crystals creating a highly interconnected nacl matrix fig1 a b fused salt molds were bisected and imaged prior to solvent casting to observe the extent of nacl crystal fusion in addition polymer scaffolds were bisected after preparation via freeze fracture a carbon coating was evaporated onto the surface of each bisected salt mold and polymer scaffold and samples were imaged under high vacuum using a hitachi s 3200n sem operating at 20 30 kv fusion of salt crystals prior to addition of plg in chloroform solvent casting resulted in enhanced pore interconnectivity within the scaffold the pore structure within the scaffolds fig2 appears similar to the structure of the fused salt matrix fig1 a b as expected pores within the cross section of 1 hr salt fusion sf samples display a defined pore structure with intermittent holes in pore walls fig2 a 2 c while the cross section of scaffolds created from 24 hr sf samples display a.