Pore size effects on convective flow and diffusion through nanoporous silica gels
Artikel i vetenskaplig tidskrift, 2015
Material structure has great impact on mass transport properties, a relationship that needs to be understood on several length scales. Describing and controlling the properties of flow through soft materials are both challenges concerning the industrial use of gel structures. This paper reports on how the porous structure in nanoporous materials affects the water transport through them. We used three different silica gels with large differences in the pore sizes but of equal silica concentration. Particle morphology and gel structure were studied using high-resolution transmission electron microscopy and image analysis to estimate the pore size distribution and intrinsic surface area of each gel. The mass transport was studied using a flow measurement setup and nuclear magnetic resonance diffusometry. The average pore size ranged from approximately 500. nm down to approximately 40. nm. An acknowledged limit for convective flow to occur is in the pore size range between 100 and 200. nm. The results verified the existence of a non-linear relationship between pore size and liquid flow at length scales below 500. nm, experimentally. A factor of 4.3 in flow speed separated the coarser gel from the other two, which presented almost identical flow speed data despite a factor 3 in pore size difference. In the setup, the mass transport in the gel with the largest pores was flow dominated, while the mass transport in the finer gels was diffusion dominated. Besides providing new insights into mass transport as a function of pore sizes, we conclude that three-dimensional analysis of the structures is needed for a comprehensive understanding of the correlation between structure and mass transport properties.
Mass transport
Liquid permeability
Nanoporous
Silica gel
Model material
Författare
Charlotte Hamngren Blomqvist
Chalmers, Teknisk fysik, Eva Olsson Group
SuMo Biomaterials
Christoffer Abrahamsson
SuMo Biomaterials
Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi
Tobias Gebäck
Chalmers, Matematiska vetenskaper, Matematik
SuMo Biomaterials
Göteborgs universitet
Annika Altskär
Structure and Material Design
SuMo Biomaterials
Anne-Marie Hermansson
SuMo Biomaterials
Chalmers, Biologi och bioteknik, Livsmedelsvetenskap
Magnus Nydén
University of South Australia
SuMo Biomaterials
Stefan Gustafsson
Chalmers, Teknisk fysik, Eva Olsson Group
SuMo Biomaterials
Niklas Lorén
Chalmers, Teknisk fysik, Eva Olsson Group
SuMo Biomaterials
Eva Olsson
Chalmers, Teknisk fysik, Eva Olsson Group
SuMo Biomaterials
Colloids and Surfaces A: Physicochemical and Engineering Aspects
0927-7757 (ISSN)
Vol. 484 288-296Enabling Science and Technology through European Electron Microscopy (ESTEEM 2)
Europeiska kommissionen (FP7), 2012-10-01 -- 2016-09-30.
Styrkeområden
Nanovetenskap och nanoteknik (SO 2010-2017, EI 2018-)
Materialvetenskap
Ämneskategorier
Fysik
Annan materialteknik
DOI
10.1016/j.colsurfa.2015.07.032