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Interconnectivity imaged in three dimensions: Nano-particulate silica-hydrogel structure revealed using electron tomography

Charlotte Hamngren Blomqvist (Institutionen för fysik, Eva Olsson Group (Chalmers) ; SuMo Biomaterials) ; Tobias Gebäck (Institutionen för matematiska vetenskaper, Tillämpad matematik och statistik ; SuMo Biomaterials) ; A. Altskar ; Anne-Marie Hermansson (Institutionen för biologi och bioteknik, Livsmedelsvetenskap ; SuMo Biomaterials) ; Stefan Gustafsson (Institutionen för fysik, Eva Olsson Group (Chalmers)) ; Niklas Lorén (Institutionen för fysik, Eva Olsson Group (Chalmers) ; SuMo Biomaterials) ; Eva Olsson (Institutionen för fysik, Eva Olsson Group (Chalmers) ; SuMo Biomaterials)
Micron (0968-4328). Vol. 100 (2017), p. 91-105.
[Artikel, refereegranskad vetenskaplig]

We have used Electron Tomography (ET) to reveal the detailed three-dimensional structure of particulate hydrogels, a material category common in e.g. controlled release, food science, battery and biomedical applications. A full understanding of the transport properties of these gels requires knowledge about the pore structure and in particular the interconnectivity in three dimensions, since the transport takes the path of lowest resistance. The image series for ET were recorded using High-Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM). We have studied three different particulate silica hydrogels based on primary particles with sizes ranging from 3.6 nm to 22 nm and with pore-size averages from 18 nm to 310 nm. Here, we highlight the nanostructure of the particle network and the interpenetrating pore network in two and three dimensions. The interconnectivity and distribution of width of the porous channels were obtained from the three-dimensional tomography studies while they cannot unambiguously be obtained from the two-dimensional data. Using ET, we compared the interconnectivity and accessible pore volume fraction as a function of pore size, based on direct images on the nanoscale of three different hydrogels. From this comparison, it was clear that the finest of the gels differentiated from the other two. Despite the almost identical flow properties of the two finer gels, they showed large differences concerning the accessible pore volume fraction for probes corresponding to their (two-dimensional) mean pore size. Using 2D pore size data, the finest gel provided an accessible pore volume fraction of over 90%, but for the other two gels the equivalent was only 10-20%. However, all the gels provided an accessible pore volume fraction of 30-40% when taking the third dimension into account.

Nyckelord: Electron tomography, Silica nanoparticle gel, Colloidal silica gel, Porous soft materials, Accessible volume fraction, Interconnectivity



Denna post skapades 2017-08-10. Senast ändrad 2017-09-06.
CPL Pubid: 250993

 

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Institutioner (Chalmers)

Institutionen för fysik, Eva Olsson Group (Chalmers)
SuMo Biomaterials
Institutionen för matematiska vetenskaper, Tillämpad matematik och statistikInstitutionen för matematiska vetenskaper, Tillämpad matematik och statistik (GU)
Institutionen för biologi och bioteknik, Livsmedelsvetenskap

Ämnesområden

Fysikalisk kemi

Chalmers infrastruktur

 


Projekt

Denna publikation är ett resultat av följande projekt:


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