Universiti Teknologi Malaysia Institutional Repository

Controlling three-dimensional ice template via two-dimensional surface wetting

Yang, Miao and Wu, Jingjun and Bai, Hao and Tao, Xie and Zhao, Qian and Wong, Tuck Whye (2016) Controlling three-dimensional ice template via two-dimensional surface wetting. AICHE Journal, 62 (12). pp. 4186-4192. ISSN 15475905

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Official URL: http://dx.doi.org/10.1002/aic.15509


Directional freezing (DF) is a fast, scalable, and environmental friendly technique for fabricating monoliths with long- range oriented pores, which can be applied toward a wide variety of materials. However, the pore size is typically larg- er than 20 l m and cannot be spatially controlled, which prevent the technique from being used more widely. In this work, effect of wettability of the freezing substrate on the pore size of monolithic polyethylene glycol cryogels is studied. Smaller pores can be generated via more hydrophilic substrates, and tubular pores smaller 5 l m can be created using a poly(vinyl alcohol) coated copper substrate. A numerical fitting between water contact angle of the substrates and pore size is then obtained. Moreover, pore size can be locally varied duplicating wetting patterns of the substrates. The concept of using two dimensional patterns to build monoliths with three dimensional microstructures can probably be extended to other material systems. DF is an effecient and scalable processing method for fabricating materials with long-range oriented pores. However, the smallest pore feature size reported is around 20 m m, which is in many cases too large for application such as separation and catalysis. We show here, with exemplary cryogels, that both spatial control and feature size reduction (by one order of magnitude) can be realized in DF by controlling the wettability of the ice growth substrate.

Item Type:Article
Additional Information:RADIS System Ref No:PB/2016/06513
Subjects:R Medicine
Divisions:Biosciences and Medical Engineering
ID Code:68141
Deposited By: Haliza Zainal
Deposited On:01 Nov 2017 03:19
Last Modified:20 Nov 2017 08:52

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