Polydopamine-Functionalized 2D Sub-Nanochannels for Efficient and Diverse Multi-Stimuli Responsive Ion Transport...

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Two-dimensional (2D) nanochannels offer unique platforms for developing smart ion channels.
• Functionalizing these channels with responsive molecules is challenging due to structural integrity requirements.

Purpose of the Study:

• To functionalize 2D nanochannels using polydopamine (PDA) for creating stable, responsive smart ion channels.
• To investigate the mechanism of ionic current modulation in PDA-functionalized 2D nanochannels.

Main Methods:

• Graphene oxide (GO) nanosheets were functionalized with polydopamine (PDA).
• PDA acted as an adhesive and partial reductant for GO, forming reduced graphene oxide (rGO) stacking.
• Ionic current measurements were performed under varying conditions (analyte interactions, temperature, ions, UV).
• Computational simulations were used to analyze surface charge density and current response.

Main Results:

• A stable 2D stacking structure of GO/PDA/rGO was successfully formed.
• PDA functionalization led to positively charged 2D channels.
• Analyte interactions with PDA induced deprotonation and a rapid increase in ionic current under confinement.
• A linear relationship was observed between current response ratio and decreasing positive charge density.
• The functionalized channels demonstrated responsiveness to temperature, potassium ions, and UV irradiation, individually and combined.

Conclusions:

• Polydopamine is an effective agent for functionalizing 2D nanochannels, enhancing stability and responsiveness.
• The developed smart ion channels exhibit tunable ionic current responses based on surface charge modulation.
• These PDA-functionalized 2D nanochannels hold promise for multi-responsive sensing applications.