Seamless joining of porous membrane with thermoplastic microfluidic devices

• We integrate porous membrane onto rigid polymer chips through 2-step bonding.
• This pre-bonding treatment reduced surface unevenness for subsequent bonding.
• We demonstrate the 2-step bonding process on >10 types of porous membranes.
• We apply the membrane integration technique on PMMA, PC and COC chips.
• The bonding is leak-proof and retains the porosity of the embedded membrane.

This paper introduces a novel fabrication method for integrating commercially available porous membranes onto thermoplastic microfluidics devices. This method involves a two-step bonding process that creates a sturdy fusion between the membrane and the rigid plastic chips. The first step is a pre-bonding treatment process, that embeds the membrane into the thermoplastic substrate with hot-embossing. This creates the initial bonding and more importantly, flatten the bonding surface by compressing the membrane onto the polymer substrate. The second step involves bonding a cover plate to the chip obtained from the earlier pre-bonding treatment process with thermal bonding. The two-step bonding technique was demonstrated through the successful integration of wide range of porous membranes such as polycarbonate (PC) track etched membrane and polyethyleneterephthalate (PET) track etched membrane. The thermoplastic substrate materials of polymethylmethacrylate (PMMA), polycarbonate (PC) and cyclic olefin copolymer (COC) were used in the experiments. The membrane retained its intrinsic porosity and was able to perform effective filtration after the integration process.

Porous membrane is seamlessly embedded in between two pieces of rigid polymer plate through a 2-step bonding process. The membrane is firstly embossed inside the bottom plate as a pre-bonding treatment, which reduces the surface unevenness and enables strong bonding between the bottom and cover plates.Figure optionsDownload as PowerPoint slide