Single polymer gating of channels under a solvent gradient.

Area of Science:

• Polymer physics
• Soft matter physics
• Statistical mechanics

Background:

• Polymers exhibit coil-globule transitions based on solvent quality.
• Understanding polymer behavior in confined spaces is crucial for nanotechnology.

Purpose of the Study:

• To investigate the coil-globule transition of polymers in a pore with a gradient of solvent quality.
• To explore potential applications of this phenomenon, such as in sensing.

Main Methods:

• Utilized a self-attracting, self-avoiding walk model for polymer simulation.
• Employed exact enumeration for short polymer chains.
• Applied transfer matrix techniques for long polymer chains.

Main Results:

• Demonstrated that a solvent quality gradient across a pore drives polymers from a good solvent to a poor solvent regime.
• Observed a gatelike effect due to the distribution of monomer density.
• Drew an analogy to thermophoresis, with polymers moving along the gradient.

Conclusions:

• A gradient in solvent quality can effectively control polymer conformation within a confined pore.
• The observed gatelike effect suggests potential for developing novel polymer-based sensors.