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DALIAN UNIVERSITY OF TECHNOLOGY Login 中文
薛春东

Associate Professor
Supervisor of Doctorate Candidates
Supervisor of Master's Candidates


Gender:Male
Alma Mater:中国科学院大学
Degree:Doctoral Degree
School/Department:生物医学工程学院
Discipline:Biomedical Engineering. Fluid Mechanics. Measuring Technology and Instrument
Business Address:厚坤楼A201
Contact Information:xuechundong@dlut.edu.cn
E-Mail:xuechundong@dlut.edu.cn
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Current position: Home >> Scientific Research >> Paper Publications

Diffusion of Nanoparticles with Activated Hopping in Crowded Polymer Solutions

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Indexed by:Journal Papers

Date of Publication:2020-05-13

Journal:NANO LETTERS

Included Journals:SCIE

Volume:20

Issue:5

Page Number:3895-3904

ISSN No.:1530-6984

Key Words:hopping diffusion; non-Gaussianity; activated energy barrier; crowded polymer solutions

Abstract:A long-distance hop of diffusive nanoparticles (NPs) in crowded environments was commonly considered unlikely, and its characteristics remain unclear. In this work, we experimentally identify the occurrence of the intermittent hops of large NPs in crowded entangled poly(ethylene oxide) (PEO) solutions, which are attributed to thermally induced activated hopping. We show that the diffusion of NPs in crowded solutions is considered as a superposition of the activated hopping and the reptation of the polymer solution. Such activated hopping becomes significant when either the PEO molecular weight is large enough or the NP size is relatively small. We reveal that the time-dependent non-Gaussianity of the NP diffusion is determined by the competition of the short-time relaxation of a polymer entanglement strand, the activated hopping, and the long-time reptation. We propose an exponential scaling law tau(hop)/tau(e) similar to exp(d/d(t)) to characterize the hopping time scale, suggesting a linear dependence of the activated hopping energy barrier on the dimensionless NP size. The activated hopping motion can only be observed between the onset time scale of the short-time relaxation of local entanglement strands and the termination time scale of the long-time relaxation. Our findings on activated hopping provide new insights into long-distance transportation of NPs in crowded biological environments, which is essential to the delivery and targeting of nanomedicines.