Controlled freezing and freeze drying: a versatile route for porous and micro-/nano-structured materials

Journal of Chemical Technology & BiotechnologyVolume 86, Issue 2 p. 172-184 Review Controlled freezing and freeze drying: a versatile route for porous and micro-/nano-structured materials† Lei Qian, Lei Qian Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UKSearch for more papers by this authorHaifei Zhang, Corresponding Author Haifei Zhang zhanghf@liv.ac.uk Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UKDepartment of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.===Search for more papers by this author Lei Qian, Lei Qian Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UKSearch for more papers by this authorHaifei Zhang, Corresponding Author Haifei Zhang zhanghf@liv.ac.uk Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UKDepartment of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK.===Search for more papers by this author First published: 02 September 2010 https://doi.org/10.1002/jctb.2495Citations: 316 † This paper was presented at The 2009 Annual Meeting of The Chinese Society of Chemical Science and Technology in the UK (CSCST) & The Society of Chemical Industry—Chinese UK Section (SCI—CS). Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Freeze drying is a process whereby solutions are frozen in a cold bath and then the frozen solvents are removed via sublimation under vacuum, leading to formation of porous structures. Pore size, pore volume and pore morphology are dependent on variables such as freeze temperature, solution concentration, nature of solvent and solute, and the control of the freeze direction. Aqueous solutions, organic solutions, colloidal suspensions, and supercritical CO2 solutions have been investigated to produce a wide range of porous and particulate structures. Emulsions have recently been employed in the freeze drying process, which can exert a systematic control on pore morphology and pore volume and can also lead to the preparation of organic micro- and nano-particles. Spray freezing and directional freezing have been developed to form porous particles and aligned porous materials. This review describes the principles, latest progress and applications of materials prepared by controlled freezing and freeze drying. First of all the basics of freeze drying and the theory of freezing are discussed. Then the materials fabricated by controlled freezing and freeze drying are reviewed based on their morphologies: porous structures, microwires and nanowires, and microparticles and nanoparticles. The review concludes with new developments in this area and a brief look into the future. Copyright © 2010 Society of Chemical Industry Citing Literature Volume86, Issue2February 2011Pages 172-184 RelatedInformation