A Sustainable freeze-drying route to porous polysaccharides with tailored hierarchical meso- and macroporosity

Aleksandra Borisova, Mario De Bruyn, Vitaliy L. Budarin, Peter S. Shuttleworth, Jennifer R. Dodson, Mateus L. Segatto, James H. Clark*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Bio-derived polysaccharide aerogels are of interest for a broad range of applications. To date, these aerogels have been obtained through the time- and solvent-intensive procedure of hydrogel fomation, solvent exchange, and scCO2 drying, which offers little control over meso/macropore distribution. A simpler and more versatile route is developed, using freeze drying to produce highly mesoporous polysaccharide aerogels with various degrees of macroporosity. The hierarchical pore distribution is controlled by addition of different quantities of t-butanol (TBA) to hydrogels before drying. Through a systematic study an interesting relationship between the mesoporosity and t-butanol/water phase diagram is found, linking mesoporosity maxima with eutectic points for all polysaccharides studied (pectin, starch, and alginic acid). Moreover, direct gelation of polysaccharides in aqueous TBA offers additional time savings and the potential for solvent reuse. This finding is a doorway to more accessible polysaccharide aerogels for research and industrial scale production, due to the widespread accessibility of the freeze drying technology and the simplicity of the method. Hierarchical polysaccharide aerogels with tailored meso/macropore structure are generated with a novel freeze-drying route. An interesting relationship between the water/t-butanol phase diagram and the porous network is discussed, and the role of the eutectic phase in tailoring the porosity is revealed. The route offers significant time and solvent savings and allows for solvent reuse.

Original languageEnglish
Pages (from-to)774-779
Number of pages6
JournalMacromolecular Rapid Communications
Issue number8
Early online date26 Feb 2015
Publication statusPublished - Apr 2015


  • biological materials
  • hierarchical materials
  • material science
  • polymers
  • porous materials

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