Synthesis and structural characterization of potato starch sponges

Materials with hierarchical porous structures have attracted great attention over the past years since they have been widely used in many industrial applications. Starch stands out among the materials commonly used as sacrificial templates in environmentally friendly applications. In addition, starch is inexpensive, easy to process, and readily available. In this work we present a structural characterization of sponges prepared by freezing and thawing of a starch gel. Samples obtained in this study were examined by scanning electron microscopy (SEM) and X-ray microtomography (μ-CT). SEM tests revealed that these samples show an open macroporous framework with continuous walls. μ-CT tests revealed that it is possible to tailor the pore structure of these materials by changing the starch concentration in gels used in their processing. We noticed that increasing starch concentration from 15 wt.% to 60 wt.% leads to sponges with porosities ranging from about 28% to over 65%. It was also observed that the higher the starch concentration, the greater the mean pore size of the prepared sponge.