Abstract
Nanochannels with controllable gating behavior are attractive features in a wide range of nanofluidic applications including viral detection, particle sorting, and flow regulation. Here, we use selective sidewall functionalization of nanochannels with a polyelectrolyte brush to investigate the channel gating response to variations in solution pH and ionic strength. The conformational and structural changes of the interfacial brush layer within the channels are interrogated by specular and off-specular neutron reflectometry. Simultaneous fits of the specular and off-specular signals, using a dynamical theory model and a fitting optimization protocol, enable detailed characterization of the brush conformations and corresponding channel geometry under different solution conditions. Our results indicate a collapsed brush state under basic pH, equivalent to an open gate, and an expanded brush state representing a partially closed gate upon decreasing the pH and salt concentration. These findings open new possibilities in noninvasive in situ characterization of tunable nanofluidics and lab-on-chip devices with advanced designs and improved functionality.
Original language | English |
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Pages (from-to) | 54942-54951 |
Number of pages | 10 |
Journal | ACS Applied Materials and Interfaces |
Volume | 15 |
Issue number | 47 |
DOIs | |
State | Published - 2023 |
Funding
R.A. and H.R. acknowledge support by research funds from the State of Virginia. C.K.O. and W.L.C. acknowledge NSF Grants CHE-2003588 and CHE-2304838 for partial support of this work. Contributions from W.B. and J.F.A. are based on work supported by Oak Ridge National Laboratory. Research conducted at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The Oak Ridge National Laboratory is managed by UT-Battelle, LLC under US DOE contract no. DE-AC05-00OR22725.
Funders | Funder number |
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Scientific User Facilities Division | |
state of Virginia | |
National Science Foundation | CHE-2003588, CHE-2304838 |
U.S. Department of Energy | DE-AC05-00OR22725 |
Basic Energy Sciences | |
Oak Ridge National Laboratory | |
UT-Battelle |
Keywords
- brush conformations
- dynamical theory analysis
- neutron reflectometry
- off-specular scattering
- pH-response
- polyelectrolyte polymers