Thermally activated solvent bonding of polymers

Abstract

We present a thermally activated solvent bonding technique for the formation of embedded microstructures in polymer. It is based on the temperature dependent solubility of polymer in a liquid that is not a solvent at room temperature. With thermal activation, the liquid is transformed into a solvent of the polymer, creating a bonding capability through segmental or chain interdiffusion at the bonding interface. The technique has advantages over the more commonly used thermal bonding due to its much lower operation temperature (30°C lower than the material's T g ), lower load, as well as shorter time. Lap shear test indicated bonding shear strength of up to 2.9 MPa. Leak test based on the bubble emission technique showed that the bonded microfluidic device can withstand at least six bars (87 psi) of internal pressure (gauge) in the microchannel. This technique can be applied to other systems of polymer and solvent.

CO2-assisted thermal fusion bonding of heterogeneous materials by use of surface nano-pillars

“…The bonding strength can be calculated from the maximum allowed shearing force measured by a material testing machine (Insight 10KN, MTS) (Ng et al 2008;Studer et al 2002). The bonding strength can be obtained by dividing the maximum recorded shearing force by the overlap area.…”

“…Plastics are essential materials for these components (Ng et al 2008). Usually, to make a product, manufacturing uses different plastic materials that have different properties, which in turn renders the final product with characteristic properties of all the materials used.…”

A low temperature ultrasonic bonding method for PMMA microfluidic chips

“…However, the whole polymer substrates with solvent on the surface of microstructures are heated up to a relatively high temperature in the process, in which it takes a risk of damaging the microstructures by solvent as well. Moreover, the whole process usually takes more than 10 min to heat up and cool down the whole chip (Ng et al 2008;Hsu and Chen 2007) in this method. If the input energy is focused on the specific locations of the substrate, getting a relatively high local temperature while the other part of the substrate is still at room temperature, damages of microstructures by solvent is prevented.…”

Solvent bonding of poly(methyl methacrylate) microfluidic chip using phase‐changing agar hydrogel as a sacrificial layer

“…Recently, Tsao and DeVoe published a review that summarized the strategies for the bonding of thermoplastic polymer microfluidic chips [5]. A variety of techniques have been developed for bonding PMMA microchips, including thermal bonding [6][7][8][9], solvent bonding [10][11][12][13][14][15][16][17], in situ polymerization bonding [18], microwave bonding [19,20], glue bonding [21], thermal lamination [22], plasticizer-assisted bonding [23], etc. Among them, various thermal bonding techniques have been widely used because they allow the formation of microchannels with uniform surfaces composed entirely of the same polymeric materials [5][6][7][8][9].…”