Siddhartha Das1 Raja Maheedhara1 Parth Rakesh Desai1 Haoyuan Jing1 Harnoor Sachar1

1, University of Maryland, College Park, Maryland, United States

Liquid flows in nanocahannels grafted with polyelectrolyte brushes have been invariably retarded owing to the significant drag force imparted by the PE brushes. In a recent study, we proposed a paradigm shift in this understanding – we showed that for nanochannels grafted with end-charged brushes (having a charge density of σ), the electroosmotic (EOS) transport got massively augmented as compared to the brush free nanochannels having a wall charge density of σ. We argued that the presence of the end-charged brushes localized the charge density of the induced electric double layer (EDL) and hence localized the EOS body force away from the nanochannel wall, thereby ensuring a massive manifestation of the EOS body force eventually enforcing a larger EOS transport. Here we report our first Molecular Dynamics (MD) simulations based verification of this phenomenon. Furthermore, we carry out continuum calculations for the diffusioosmotic (DOS) and thermooosmotic (TOS) transport in such end-charged PE-brush-grafted nanochannels in presence of an axial concentration and an axial temperature gradient respectively to establish that these transports too get enhanced due to the corresponding enhancement in the induced EOS transport. Furthermore, MD simulations are carried out to validate the continuum findings.