Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electric-field-enhanced transport in polyacrylamide hydrogel
  nano-composites   Electroosmotic pumping through uncharged hydrogels can be achieved by
embedding the polymer network with charged colloidal inclusions. Matos and
co-workers (2006) recently used the concept to enhance the diffusion-limited
flux of uncharged molecules across polyacrylamide hydrogel membraness for the
purpose of improving the performance of biosensors. This paper seeks to link
their reported macroscale diagnostics to physicochemical characteristics of the
composite microstructure. A mathematical model for the bulk electroosmotically
enhanced tracer flux is proposed, which is combined with the electrokinetic
model to ascertain the electroosmotic pumping velocity from measured flux
enhancements. Because the experiments are performed with a known current
density, but unknown bulk conductivity and electric field strength, theoretical
estimates of the bulk electrical conductivity are adopted. These account for
nano-particle polarization, added counterions, and non-specific adsorption.
Theoretical predictions of the flux enhancement, achieved without any fitting
parameters, are within a factor of two of the experiments. Alternatively, if
the Brinkman screening length of the polymer skeleton is treated as a fitting
parameter, then the best-fit values are bounded by the range 0.9-1.6 nm,
depending on the inclusion size and volume fraction. Independent
pressure-driven flow experiments reported in the literature for polyacrylamide
gels without inclusions suggest 0.4 or 0.8 nm. The comparison can be improved
by allowing for hindered ion migration, while uncertainties regarding the
inclusion surface charge are demonstrated to have a negligible influence on the
electroosmotic flow.

22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph