English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We report observations of a remarkable scaling behavior with respect toconcentration in the passive microbead rheology of two highly entangledpolymeric solutions, polyethylene oxide (PEO) and hyaluronic acid (HA). Thisbehavior was reported previously [Hill et al., PLOS ONE (2014)] for human lungmucus, a complex biological hydrogel, motivating the current study forsynthetic polymeric solutions PEO and HA. The strategy is to identify, andfocus within, a wide range of lag times ${\tau}$ for which passive microndiameter beads exhibit self-similar (fractional, power law)mean-squared-displacement (MSD) statistics. For lung mucus, PEO at threedifferent molecular weights (Mw), and HA at one Mw, we find ensemble-averagedMSDs of the form ${\langle}{\Delta}r^{2}({\tau}){\rangle} =4D_{\alpha}{\tau}^{\alpha}$, all within a common band, [1/60 sec, 3 sec], oflag times ${\tau}$. We employ the MSD power law parameters$(D_{\alpha},{\alpha})$ to classify each polymeric solution over a range ofhighly entangled concentrations. By the generalized Stokes-Einstein relation,power law MSD implies power law elastic $G'({\omega})$ and viscous$G''({\omega})$ moduli for frequencies $1/{\tau}$, [0.33 sec$^{-1}$, 60sec$^{-1}$]. A natural question surrounds the polymeric properties that dictate$D_{\alpha}$ and ${\alpha}$, e.g. polymer concentration c, Mw, and stiffness(persistence length). In [Hill et al., PLOS ONE (2014)], we showed the MSDexponent ${\alpha}$ varies linearly, while the pre-factor $D_{\alpha}$ variesexponentially, with concentration, i.e. the semi-log plot,$(log(D_{\alpha}),{\alpha})(c)$ of the classifier data is collinear. Here weshow the same result for three distinct Mw PEO and HA at a single Mw. Futurestudies are required to explore the generality of these results for polymericsolutions, and to understand this scaling behavior with polymer concentration.

Evidence that self-similar microrheology of highly entangled polymeric solutions scales robustly with, and is tunable by, polymer concentration