Active nematic pumps

TL;DR

This paper demonstrates that adding triangular inclusions to active nematic gels can create self-powered microfluidic pumps capable of cargo transport and mixing, leveraging active fluid self-organization.

Contribution

It introduces a novel method to generate self-pumping microfluidic systems using active nematic gels with engineered inclusions, enabling autonomous flow control.

Findings

Active inclusions break symmetry and stabilize flow fields.

The pumps can generate significant flow and pressure autonomously.

Strategies for integrating these pumps into microfluidic devices are proposed.

Abstract

Microfluidics involves the manipulation of flows at the microscale, typically requiring external power sources to generate pressure gradients. Alternatively, harnessing flows from active fluids, which are usually chaotic, has been proposed as a paradigm for the development of micro-machines. Here, by combining experimental realizations and simulations, we demonstrate that the addition of triangular-shaped inclusions into an active nematic gel can locally break the fore-aft symmetry of active turbulence and stabilize flow fields with self-pumping capabilities. The proposed strategy has enabled us to generate wall-free and self-powered microfluidic systems capable of both cargo transport and mixing along with the downstream flow. We analyze the performance of these active pumps, both isolated and within cooperative ensembles in terms of their output velocity and hydrostatic pressure buildup. Finally, we demonstrate strategies to incorporate them into specifically designed microfluidic platforms to advantageously tailor the geometry of active flows. Our results reveal new possibilities for leveraging the self-organized mechanodynamics of active fluids.