Diffusion of rigid nanoparticles in crowded polymer-network hydrogels: dominance of segmental density over crosslinking density

Invited Article

DOI: 10.1007/s00396-017-4069-x

Cite this article as:
Walta, S., Di Lorenzo, F., Ma, K. et al. Colloid Polym Sci (2017). doi:10.1007/s00396-017-4069-x


Swollen polymer-network gels usually exhibit notable spatial inhomogeneity of their crosslinking density. The effect of this inhomogeneity on the permeability of the gel to small particles is of major importance in many applications such as those in analytical separation technology. To systematically address this effect, we mimic inhomogeneous polymer-network gels by dense-packed pastes of sub-micrometer-sized microgel building blocks with two distinctly different crosslinking degrees. The diffusive mobility of rigid nanoparticle tracers within these inhomogeneous pastes that contain purposely imparted densely and loosely cross-linked local domains is studied by spatially resolved dual-focus fluorescence correlation spectroscopy on a sub-micrometer length scale. The outcome of this investigation is that the sub-micrometer-scale tracer diffusivity of the tracers is not affected by the gel-matrix crosslinking density, and hence, also not by its spatial inhomogeneity. Instead, the tracer diffusion is dominantly hindered by the high density of polymer segments in the deswollen gel matrixes.


Microgels Hydrogels Tracer diffusion Crowding Fluorescence Fluorescence correlation spectroscopy C-dots 

Supplementary material

396_2017_4069_MOESM1_ESM.pdf (1.5 mb)
ESM 1(PDF 1500 kb)

Funding information

Funder NameGrant NumberFunding Note
National Cancer Institute of the National Institutes of Health
  • U54CA199081

Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  1. 1.RWTH Aachen UniversityInstitute of Physical Chemistry, JARA, Soft Matter ScienceAachenGermany
  2. 2.Physical-Chemistry DepartmentAdocia SALyonFrance
  3. 3.Department of Materials Science and EngineeringCornell UniversityIthacaUSA
  4. 4.Johannes Gutenberg-Universität MainzInstitute of Physical ChemistryMainzGermany

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