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Updated: Sep 21, 2025

Single-Molecule Diffusion and Assembly on Polymer-Crowded Lipid Membranes
Published on: July 19, 2022
Density of Obstacles Affects Diffusion in Adsorbed Polymer Layers
Cristian Rodríguez-Tinoco1, David Nieto Simavilla1, Rodney D Priestley2
1Laboratory of Polymer and Soft Matter Dynamics, Experimental Soft Matter and Thermal Physics (EST), Faculté des Sciences, Université libre de Bruxelles (ULB), Boulevard du Triomphe, Bruxelles 1050, Belgium.
Abstract:
The translational diffusion of molecules dispersed into polymer matrices slows down tremendously when approaching a nonrepulsive interface. To unravel the origin of this phenomenon, we investigated the diffusion of molecular probes in the direction normal to an adsorbing wall. Using adsorbed polymer layers as matrices, we were able to decouple interfacial and finite size effects and determined the relation between the diffusion time and the area available at the polymer/solid interface. Based on the results of our investigation, we present a physical picture, suggesting that the reduction in diffusion rate is correlated to the degree of chain adsorption onto the substrate, that is, the density of surface obstacles encountered by tracer molecules.
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