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Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures
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Diffusive dynamics of charged nanoparticles in convex lens-induced confinement
Emmanuel Hitimana1, Brittany K Roopnarine1, Svetlana Morozova1
1Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, USA. sam381@case.edu.
Soft Matter
|January 4, 2022
Summary
Particle diffusion slows in confined spaces, with hindrance increasing with greater confinement. Concentration and salt levels affect particle movement and surface adsorption in these studies.
Area of Science:
- Colloid and Surface Science
- Soft Matter Physics
- Microfluidics
Background:
- Transport in confined geometries is crucial for filtration, drug delivery, and oil recovery.
- Understanding particle dynamics in varying confinement is essential for optimizing these processes.
Purpose of the Study:
- To investigate the dynamics of nanoparticles in tunable confined geometries.
- To quantify the effects of confinement, concentration, and ionic strength on particle diffusion.
Main Methods:
- Utilized differential dynamic microscopy (DDM) and particle tracking.
- Employed a convex lens-induced confinement (CLiC) device with controllable gap heights from 0.085 μm to 3.6 mm.
- Analyzed particle dynamics across various concentrations and ionic strengths using fluorescence microscopy.
Main Results:
- Particle diffusion was significantly hindered with increasing confinement.
- The ensemble-averaged diffusion coefficient depended on bulk concentration, with this dependence intensifying under confinement.
- Higher particle and salt concentrations promoted confinement-dependent adsorption to the geometry surface.
Conclusions:
- CLiC devices offer a versatile platform for studying dynamics across a wide range of confinement scales (sub-100 nm to hundreds of μm).
- Findings enhance understanding of particle behavior in confined environments, impacting separation and interaction studies.
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