and sieved salt crystals ranging from 25 to 50mm and 50 to 100mm. Sieved salt crystals were prepared by grinding NaCl crystals using a mortar and pestle and then selecting crystals sizes using sieves (Precision E-forming LL, Cortland, NY). For smaller pores the crystals precipitated from the saturated salt solution were prepared as described in the paragraph above. All gels
and sieved salt crystals ranging from 25 to 50mm and 50 to 100mm. Sieved salt crystals were prepared by grinding NaCl crystals using a mortar and pestle and then selecting crystals sizes using sieves (Precision E-forming LL, Cortland, NY). For smaller pores the crystals precipitated from the saturated salt solution were prepared as described in the paragraph above. All gels were made in 1.5mL centrifuge tubes resulting in conelike structures (Fig. 2). One hundred milligrams of salt particles was dissolved into 200mL of hydrogel precursor. The salt particles and precursor were vortexed to minimize aggregation. In one condition, gels containing sieved salt crystals were immediately polymerized after ad-dition of the salt crystals (‘‘static’’), whereas in the other condition gels were centrifuged to pack the salt crystals be-fore polymerization (‘‘centrifuged’’). Both solutions were polymerized under UV light (365nm) for 5min. The salts were leached out of the gel by incubation in deionized water (DI) water changed every 2h for 8h. The gels were then incubated in DI water overnight. The nonporous gels were prepared by polymerizing the saturated precursor solution without the addition of salt crystals.