Fractional Separation of Polymers in Nanochannels: Combined Influence of Wettability and Structure

TL;DR

This paper proposes a novel fractional segregation technique for polymers in nanochannels that leverages wettability and structure to achieve selective trapping, enabling structure-based biopolymer separation without complex channel designs.

Contribution

It introduces a new mechanism combining wettability and polymer structure to selectively trap polymers in nanochannels, advancing separation methods.

Findings

Polymer segregation depends on wettability and structure.

The method enables structure-based separation without complex geometries.

The approach predicts polymer trapping levels based on properties.

Abstract

Trapping macromolecules in nanopits finds multifarious applications in polymer separation, filtering biomolecules etc. However, tuning the locomotion of polymers in channels of nanoscopic dimensions is greatly restricted by the comparative advective and diffusive components of velocities. Using the polymer affinity toward the solvent and the wall, and the polymer structure, a mechanism is proposed to induce selective trapping of polymers. Similar to fractional distillation of hydrocarbons based on molecular weight, a technique of fractional segregation, depending on the channel wettability of polymeric chains at different depths in a pit that is located perpendicular to the flow is suggested. Depending on the properties of the polymeric chains and the surface chemistry, the segregation of the polymer at a particular level in the pit can be predicted. This behaviour stems from the difference in polymer structure leading to a competition between wettability based trapping and entropic trapping. The results of this study suggest a novel way of separating biopolymers based on their structure without relying on the channel geometry.