CO₂-laser micromachining of PMMA: the effect of polymer molecular weight

Abstract

This paper reports an investigation on the effects of laser power and processing speed on the depth, width and surface profiles of microchannels manufactured from polymethyl methacrylate (PMMA) of various molecular weights. The CO 2 laser employed has a wavelength of 10.6 µm and a maximum power of 25 W. The power used for channel fabrication varied between 0.275 and 2.5 W and the cutting speed ranged from 7.0 to 64 mm s −1 . It is observed that the channel depth varies linearly with an increase in laser power at a particular speed. For a prescribed laser power, the channel depth decreased with an increase in laser speed for all the grades of PMMA. The channel width increased with an increase in laser power but decreased with an increase in speed. There is a decrease in the depth of the microchannels with an increase in the molecular weight of PMMA. Though the width decreases with an increase in molecular weights of PMMA, 96.7 kDa PMMA has a smaller width than 120 kDa PMMA which is due to the formation of bulges on the channel rim. The surface profiles of the microchannels were examined by a scanning electron microscope. It is observed that pore formation increased with an increase in molecular weight.

CO2 Laser Manufacturing of Miniaturised Lenses for Lab-on-a-Chip Systems

“…Of these fabrication processes, CO 2 laser engraving is an attractive alternative to established micro-manufacturing techniques for the production of optical components, and such a technology has a rapid turnaround time and does not require fixed photomasks, embossing tools or a clean room environment and is suited to polymer manufacturing, a substrate most commonly used for the fabrication of various microsystems [8,9,[21][22][23][24][25]. However, without adequate post-processing, the quality of manufactured microfluidics and the surface quality of the lenses are poor compared to techniques, such as photolithography or thermal reflow.…”

Planar lens integrated capillary action microfluidic immunoassay device for the optical detection of troponin I

“…[19][20][21][22][23][24][25][26] However, the quality of manufactured microfluidics and the surface quality of the lenses are better defined, with fewer manufacturing defects using techniques such as photolithography.…”

Fabrication of polystyrene microfluidic devices using a pulsed CO2 laser system

“…During recent years, microfluidics has emerged as an advanced technique for analytical, biological, diagnostics and biomedical research (Jakeway et al 2000;Nayak et al 2008). As a subcategory of microfluidics, droplet microfluidics is very attractive for its potential to generate and manipulate discrete droplets in continuous flow, thus allowing for independent control of each droplet to act as microreactors that can be individually transported, mixed and analyzed (Link et al 2006;Fair 2007).…”

“…Compared with conventional materials like silicon and glass, polymers have become more and more attractive to fabricate microfluidic devices because of their many advantages, such as low cost and ease of fabrication (Duffy et al 1998;Dolink et al 2000;Nayak et al 2008). Many kinds of polymers have been used to fabricate microfluidic devices, such as Poly(methylmethacrylate) (PMMA) Reedy et al 2011), polystyrene (PS) (Darain et al 2009;Young et al 2011), polydimethylsiloxane (PDMS) (Hoek et al 2010;Pla-Roca and Juncker 2011), polycarbonate (PC) (Ogonczyk et al 2010;Jankowski et al 2011) and Polytetrafluoroethylene (PTFE) (Fair 2007).…”

“…Compared with the commonly used polymer microfabrication techniques such as hot-embossing (Martynova, et al 1997;Gerlach et al 2002), injection molding (Rotting et al 2002), and photolithography (Lim et al 2009), laser direct-writing micromachining is very promising because of its low cost, fast speed and non-contact characteristics (Nayak et al 2008;Yi et al 2010).…”