https://orcid.org/0000-0002-0680-8073
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Abstract
Control of pore opening is a valuable contribution to ensure filtration and separation of particles and cells of different sizes. These can be, e.g. blood cells with their cell distribution width, which is typically measured in the Complete Blood Count. In the current work, we investigate hydrogel pores made of pNIPAAm with swelling and de-swelling capabilities. They react to variations in ethanol concentration. Additionally, we analyze the effect of microfluidic pressure on membrane pores. Furthermore, the influence of the gel volume for cross-shaped pores is shown. For this purpose, experimental and numerical investigations are performed. An analogy model for the swelling behavior based on the Temperature-Expansion-Model from our previous work and a neo-Hookean material description is applied to describe swelling and mechanical deformation of the pores. Simulation results show a negligible influence to the pore bending in the specified pressure range. In the experiments, only a slight change in the pore area is observed under pressure variation. Nonetheless, there is a very good agreement between numerical and experimental results. The current investigations show the potential for the mechanical description of hydrogel pores for their further geometric optimization.
Disclosure statement
No potential conflict of interest was reported by the authors.
CRediT authorship contribution statement
EL: Conceptualization, Validation, Formal analysis, Investigation, Writing - Original Draft, Visualization DG: Conceptualization, Methodology, Validation, Investigation, Writing - Original Draft, Visualization RM: Conceptualization, Validation, Formal analysis, Investigation, Writing - Original Draft FO: Writing - Review AE: Conceptualization, Formal analysis, Writing - Review & Editing SG: Investigation/Experiments GKA: Designing, performing and interpreting rheological experiments SM: Methodology, Designing, performing and interpreting rheological experiments AR: Writing - Review, Supervision, Project administration, Funding acquisition TW: Writing - Review & Editing, Supervision, Project administration, Funding acquisition
Figure A1. Illustration of a clamped circular plate under constant pressure. The outer circular plate consists of PET and the inner circular plate is made of hydrogel. The dimensions are: a = 600 µm, b = 2000 µm. The load is
Figure A2. Comparison of the bending and the torsion of the circular plate with and without the outer ring plate of PET.
(a) Bending line of the circular plate with the outer ring plate made of PET and the inner circular plate made of hydrogel. Due to the low bending in the PET region, the deformation in the hydrogel region is close to the deformation of the hydrogel plate when clamped at r = a.
(b) The torsion of the circular plate with the outer ring plate made of PET and the inner circular plate made of hydrogel corresponds in good approximation with the torsion of the hydrogel plate when clamped at r = a.
