Fabrication and modelling of injection moulded all-polymer capillary microvalves for passive microfluidic control

Abstract

Rapid prototyping is desirable when developing products. One example of such a product is all-polymer, passive flow controlled lab-on-a-chip systems that are preferential when developing low-cost disposable chips for point-of-care use. In this paper we investigate the following aspects of going from rapid prototyping to pilot (mass) production. (1) Fabrication of an all-polymer microfluidic system using a rapid prototyped master insert for injection moulding and ultrasonic welding, including a systematic experimental characterisation of chip featured geometric capillary microvalve test structures. (2) Numerical modelling of the microvalve burst pressures. Numerical modelling of burst pressures is challenging due to its non-equilibrium nature. We have implemented and tested the level-set method modified with a damped driving term and show that the introduction of the damping term leads to numerically robust results with limited computational demands and a low number of iterations. Numerical and simplified analytical results are validated against the experimental results. We find that injection moulding and ultrasonic welding are effective for chip production and that the experimental burst pressures could be estimated with an average accuracy of 5% using the presented numerical model.

Comparison of Ultrasonic Welding and Thermal Bonding for the Integration of Thin Film Metal Electrodes in Injection Molded Polymeric Lab-on-Chip Systems for Electrochemistry

“…The ultrasound energy makes the energy directors melt, allowing bonding of the two parts (Figure 1a,b). It was demonstrated that UW is a very useful tool for both self-aligned gapless welding of polymer chips and for sealing of low-aspect ratio, large-area microchannels [1,13,14,16,21,22]. Here, we focus on the use of UW for the integration of embedded metal electrodes in injection molded (IM) microfluidic chips (Figure 1b,c) made of cyclic olefin copolymer (COC).…”

A rapid, maskless 3D prototyping for fabrication of capillary circuits: Toward urinary protein detection

“…Here we defined trigger valve success as when a valve holds liquid for at least 10 min without leakage. The success rate of trigger valves is highly related to their geometries . The geometric parameters known to affect the performance of capillary trigger valves are the height and width of the trigger valve, and the height difference between the TV and the release channel (Supporting Information Fig.…”

Inner Surface Design of Functional Microchannels for Microscale Flow Control

“…Recently, they realized gas–water separation by simply constructing obstacle microstructures in the microchannels . Construction of hydrophobic obstacle microstructure in the microchannel increased the energy barrier for the flow of water, which could be explained by the Young–Laplace equation and the Gibbs inequality effect . Because of the large critical Laplace force in the outlet channel with microstructure, the water was guided into outlet channel without microstructure under a driving pressure of critical pressure, and gas flowed into another outlet channel (Figure B).…”