Fluorescent molecular rotor-based polymer materials for local microviscosity mapping in microfluidic channels

TL;DR

This paper introduces a new polymer material incorporating a molecular rotor that enables local microviscosity mapping within microfluidic channels, demonstrating potential for detailed fluid property analysis.

Contribution

Development of a viscosity-sensitive polymer with preserved rotor properties for microfluidic viscosity mapping applications.

Findings

Polymer maintains rotor fluorescence lifetime sensitivity to viscosity.

Viscosity-sensitive surfaces are robust over time and use.

Successful microfluidic viscosity mapping demonstrated.

Abstract

A viscosity-sensitive monomer consisting of a methacrylate-functionalized julolidone-based molecular rotor (MECVJ) was synthesized and used to obtain viscosity-sensitive polymers (poly(DMA-\textit{s}-MECVJ)). The qualitative properties of the molecular rotor were preserved after its inclusion in the new polymer, in particular the effect of the viscosity of the surrounding medium on the fluorescence lifetime of the rotor. By grafting these polymers onto glass slides, viscosity-sensitive surfaces were obtained, showing good robustness in time after successive use and washing. As proof of concept, these surfaces were used to assemble a microfluidic chip capable of mapping viscosity of fluids flowing inside the channel.