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Precision control of flow rate in microfluidic channels using photoresponsive soft polymer actuators

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Abstract

A novel approach that allows control of flow in microfluidic channels with unsurpassed performance using light is described. Valve structures have been created using photoresponsive hydrogels based on spiropyran-functionalised pNIPAAm hydrogels photopolymerised around pillar structures within the channels. Valve actuation is controlled from outside the fluidic system using externally located LEDs. Highly precise and accurate flow rates can be selected by passing real-time flow rate measurements into a PID algorithm. The optimised algorithm also minimises overshoot of the selected flow rate, eliminates flow rate drift, and improves the system response time. In addition to the dramatic improvements in flow rate control, the set up enables the polymer actuation behaviour to be rapidly characterised. The power supply to the LED also provides a useful system diagnostic for monitoring the performance of the valve over time. For example, degradation in the valve actuation due to photodegradation will manifest as an increasing power requirement over time, enabling predictive failure thresholds to be established for particular actuator designs and polymer compositions.

Graphical abstract: Precision control of flow rate in microfluidic channels using photoresponsive soft polymer actuators

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Publication details

The article was received on 04 Apr 2017, accepted on 17 May 2017 and first published on 17 May 2017


Article type: Paper
DOI: 10.1039/C7LC00368D
Citation: Lab Chip, 2017, Advance Article
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    Precision control of flow rate in microfluidic channels using photoresponsive soft polymer actuators

    C. Delaney, P. McCluskey, S. Coleman, J. Whyte, N. Kent and D. Diamond, Lab Chip, 2017, Advance Article , DOI: 10.1039/C7LC00368D

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