Spontaneous capillary flow in porous biomaterials



GOAL & AIM
In this project we want to study the nature of capillary action in structured microchannels with different hydrophilicity with the aim to transfer the knowledge into a real system using renewable materials with increased mass transport properties. Our vision is to be able to tailor the spontaneous capillary action of a biomaterial to our needs.

BACKGROUND
Building a sand castle, dipping a cookie in coffee, wicking of a candle, liquid flow in a diaper or the drying of mortar – all involve capillary forces. The list shows that those forces represent an important physical phenomenon in nature and in our daily life. It is understandable that broad research has been carried out to investigate the mechanisms behind capillary action or the spontaneous uptake of a liquid into a material. While the speed of a liquid in smooth and straight channels can easily be described, the existing model does not predict capillary action correct when it comes to porous 3D biomaterials. Reasons could be that (i) the material matrix absorbs liquid; (ii) voids in the materials are too wide for effective capillarity; (iii) the liquid moves discontinuously through the material; or (iv), that inertial effects are not considered. Due to the complexity of typical biomaterials, a model system is being developed in order to investigate individual effects of wicking in biomaterials, such as surface roughness of capillary walls and interconnectivity. It is fabricated in different materials using lithography techniques. The results will be compared with a real porous biomaterial, such as porous freeze-dried alginate gels or different types of cryogels.

RESEARCH QUESTIONS
- How does the structure of a porous biomaterial should look like to facilitate wicking?
- Which kind of chemical modifications promote the capillary uptake?
- Does the liquid take preferred pathways depending on the nature of the capillary channels?
- Does the introduction of roughness on the channel walls increase capillary action?

​The project is carried out in the  VINN EXCELLENCE centre  SuMo Biomaterials , financed by VINNOVA.

Published: Wed 24 Apr 2013. Modified: Wed 24 Aug 2016