Fabrication and characterization of poly(methylmethacrylate) microfluidic devices bonded using surface modifications and solvents

Abstract

The fabrication of polymer microchips allows inexpensive, durable, high-throughput and disposable devices to be made. Poly(methylmethacrylate) (PMMA) microchips have been fabricated by hot embossing microstructures into the substrate followed by bonding a cover plate. Different surface modifications have been examined to enhance substrate and cover plate adhesion, including: air plasma treatment, and both acid catalyzed hydrolysis and aminolysis of the acrylate to yield carboxyl and amine-terminated PMMA surfaces. Unmodified PMMA surfaces were also studied. The substrate and cover plate adhesion strengths were found to increase with the hydrophilicity of the PMMA surface and reached a peak at 600 kN m(-2) for plasma treated PMMA. A solvent assisted system has also been designed to soften less than 50 nm of the surface of PMMA during bonding, while still maintaining microchannel integrity. The extent to which both surface modifications and solvent treatment affected the adhesion of the substrate to the cover plate was examined using nanoindentation methods. The solvent bonding system greatly increased the adhesion strengths for both unmodified and modified PMMA, with a maximum adhesion force of 5500 kN m(-2) achieved for unmodified PMMA substrates. The bond strength decreased with increasing surface hydrophilicity after solvent bonding, a trend that was opposite to what was observed for non-solvent thermal bonding.

Safe and cost-effective rapid-prototyping of multilayer PMMA microfluidic devices

“…Intermediate adhesive layers have been proposed, but can interact with the fluid passing through the microfluidic channels. Surface modification and solvent-assisted bonding (Brown et al 2006) which can change surface shape but usually involve highly toxic chemicals (chloromethane, dichloromethane, chloroform) are other proposed methods. Furthermore, both methods can lead to clogging of the channels (Lin et al 2007).…”

Directing Cluster Formation of Au Nanoparticles from Colloidal Solution

“…The PS-b-PMMA substrates were rinsed with 50/50 v/v IPA/DI for 1 min followed by immersion in DMSO for 5 min and 1−5 min immersion in 2−5% vol % ED in DMSO to functionalize the surface PMMA regions of the substrate with amine functional groups. 58 The standard treatment of ED was for 5 min in 5 vol % ED in DMSO solution. Any deviations are clearly stated in the text.…”

Evaluation of Different Nonspecific Binding Blocking Agents Deposited Inside Poly(methyl methacrylate) Microfluidic Flow-Cells

“…The PT PMMA surface showed relatively uniform adsorption of proteins in contrast to the plain PMMA surface. It has been shown previously that the oxygen plasma treatment created carboxylic groups and other reactive radicals on the PMMA surface which could allow the binding of the proteins [35].…”