New perspectives for direct PDMS microfabrication using a CD-DVD laser

Abstract

A simple and inexpensive alternative to high-power lasers for the direct fabrication of microchannels and rapid prototyping of poly-dimethylsiloxane (PDMS) is presented. By focusing the infrared laser beam of a commercial, low-power CD-DVD unit on absorbing carbon micro-cluster additives, highly localized PDMS combustion can be used to etch the polymer, which is otherwise transparent at such wavelengths. Thanks to a precise and automated control of laser conditions, laser-induced incandescence is originated at the material surface and produces high-resolution micropatterns that present properties normally induced with lasers of much greater energies in PDMS: formation of in situ nanodomains, local fluorescence and waveguide patterns. An extensive study of the phenomenon and its performance for PDMS microfabrication are presented.

Rapid fabrication of on-demand high-resolution optical masks with a CD–DVD pickup unit

“…The choice of such a particular polymeric matrix was justified by the low cost, ease of use, and relatively low thermal conductivity (κ ∼ 0.2 W∕m · K for polyester) of this material. This indeed allows for the avoidance of thermal transport from the focal spot and promotes laser-induced incandescence in superficial carbon microclusters as described in [8]. Thanks to this particular polymeric matrix, the dark layer with embedded CNP was also very resistant to manipulation by hand and tweezers.…”

3D printing with light: towards additive manufacturing of soft, electroactive structures

“…This behavior is not surprising, considering that combustion of silicone elastomer produces silicon dioxide, silicon carbide and silicon oxycarbide 11 , all of which are very hard, brittle ceramic materials. Unfortunately, this makes laserscribed silicone rubber unsuitable as electrodes for elastic actuators and sensors.…”

“…11 In the works by Hautefeuille et al [9][10][11] , carbon particles were applied to the surface or incorporated in the silicone elastomer to absorb the laser light and locally heat the elastomer to cause combustion. We found that laser induced combustion of the UV-curable silicone used in our 3D printing process is possible without incorporation of carbon particles using a 250 mW, 405 nm violet diode laser.…”

Heat generation and conduction in PDMS-carbon nanoparticle membranes irradiated with optical fibers

“…For comparison, pure multi-walled carbon nanotubes in vacuum can reach temperatures up to~2500 K. It is expected that the polymer molecules exposed to such temperatures will decompose on the surface. While this is unfavorable for the performance of the membranes as heat delivers in the long term (lower powers will be necessary to avoid evaporation or decomposition of the surrounding matrix), this condition has been actually used to etch micropatterns in PDMS surfaces [10].…”

“…The properties of carbon allotropes mentioned so far have encouraged researchers to investigate the applications of carbon nanoparticles as heat deliverers; recent research fronts contemplate, for example, the use of carbon nanotubes for photothermal cancer treatment [9], light absorption and combustion in polymercarbon composites to produce high-resolution micropatterns [10], and light absorption in composites to induce thermocapillary pumping in micro-channels [11]. Among other interesting physical phenomena [12], the thermal properties of polymer-carbon composites have been particularly studied due to the fact that pure carbon nanoparticle blocks are not mechanically stable and have large porosities: this is the reason why it is a common practice to mix nanoparticles with a secondary phase [13].…”