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Pore size effects on convective flow and diffusion through nanoporous silica gels

Charlotte Hamngren Blomqvist (Institutionen för teknisk fysik, Eva Olsson Group ; SuMo Biomaterials) ; Christoffer Abrahamsson (Institutionen för kemi och kemiteknik, Teknisk ytkemi ; SuMo Biomaterials) ; Tobias Gebäck (Institutionen för matematiska vetenskaper, matematik ; SuMo Biomaterials) ; A. Altskär ; Anne-Marie Hermansson (Institutionen för biologi och bioteknik, Livsmedelsvetenskap ; SuMo Biomaterials) ; M. Nydén ; Stefan Gustafsson (Institutionen för teknisk fysik, Eva Olsson Group ; SuMo Biomaterials) ; Niklas Lorén (SuMo Biomaterials ; Institutionen för teknisk fysik, Eva Olsson Group ) ; Eva Olsson (Institutionen för teknisk fysik, Eva Olsson Group ; SuMo Biomaterials)
Colloids and Surfaces A: Physicochemical and Engineering Aspects (0927-7757). Vol. 484 (2015), p. 288-296.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: Liquid permeability, Mass transport, Model material, Nanoporous, Silica gel



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Denna post skapades 2015-09-14. Senast ändrad 2016-10-17.
CPL Pubid: 222446

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Eva Olsson Group (2012-2015)
SuMo Biomaterials
Institutionen för kemi och kemiteknik, Teknisk ytkemi
Institutionen för matematiska vetenskaper, matematik (2005-2016)
Institutionen för biologi och bioteknik, Livsmedelsvetenskap

Ämnesområden

Materialvetenskap
Nanovetenskap och nanoteknik
Fysik
Annan materialteknik

Chalmers infrastruktur

 


Projekt

Denna publikation är ett resultat av följande projekt:


Enabling Science and Technology through European Electron Microscopy (ESTEEM 2) (EC/FP7/312483)