Synthesis and Characterization of Stimuli-Responsive Polymer Brushes in Nanofluidic Channels

Hadi Rahmaninejad, Andrew J. Parnell, Wei Liang Chen, Nilay Duzen, Thomas Sexton, Gary Dunderdale, John F. Ankner, Wim Bras, Christopher K. Ober, Anthony J. Ryan, Rana Ashkar

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

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 languageEnglish
Pages (from-to)54942-54951
Number of pages10
JournalACS Applied Materials and Interfaces
Volume15
Issue number47
DOIs
StatePublished - 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.

FundersFunder number
Scientific User Facilities Division
state of Virginia
National Science FoundationCHE-2003588, CHE-2304838
U.S. Department of EnergyDE-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

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