Development of a rapid cure polydimethylsiloxane replication process with near-zero shrinkage

Desktop aligner for fabrication of multilayer microfluidic devices

“…19 Under the curing condition used in this work, the shrinkage ratio of PDMS is about 1%, with a variance of 0.2%. 20 This translates to an alignment error of 20 µm cm −1 when aligning two PDMS layers, very comparable to the value obtained from our experiments. To achieve higher global alignment accuracy, it has been suggested that one may need more sophisticated techniques such as sandwich mold fabrication for soft lithography.…”

“…To achieve higher global alignment accuracy, it has been suggested that one may need more sophisticated techniques such as sandwich mold fabrication for soft lithography. 20,21 Rotational error resulted from global alignments of large PDMS devices was 0.31 ± 0.06…”

Semi-Transparent Energy-Harvesting Solar Concentrator Windows Employing Infrared Transmission-Enhanced Glass and Large-Area Microstructured Diffractive Elements

“…In this study, large-area diffraction grating patterns on glass substrates were fabricated by employing a double replication process, as shown in Figure 3. A quartz master grating of periodicity 4 µm, groove depth near 0.5 µm, and 50% duty cycle fabricated by photolithography and reactive-ion etching process, was dipped in the 2% dimethyldichlorosilane dissolved in octamethylcyclooctasilane (Repel-Silane ES, GE Healthcare Co., Ltd., Chicago, IL, USA) to apply a self-assembled monolayer as an anti-adhesion layer [35][36][37]. First, a replicated polydimethylsiloxane (PDMS) master template with master grating's structures were obtained from the quartz master by utilizing the soft lithography process [35,36], using a Sylgard 184 base and curing agent mixture (Dow Corning, Midland, Michigan) with 10:1 weight ratio, poured onto the master grating and cured at room temperature.…”

“…A quartz master grating of periodicity 4 µm, groove depth near 0.5 µm, and 50% duty cycle fabricated by photolithography and reactive-ion etching process, was dipped in the 2% dimethyldichlorosilane dissolved in octamethylcyclooctasilane (Repel-Silane ES, GE Healthcare Co., Ltd., Chicago, IL, USA) to apply a self-assembled monolayer as an anti-adhesion layer [35][36][37]. First, a replicated polydimethylsiloxane (PDMS) master template with master grating's structures were obtained from the quartz master by utilizing the soft lithography process [35,36], using a Sylgard 184 base and curing agent mixture (Dow Corning, Midland, Michigan) with 10:1 weight ratio, poured onto the master grating and cured at room temperature. In the second replication step, a UV-replication process similar to the soft-lithography step was conducted on the 130 mm × 70 mm × 3 mm low-iron glass substrates using the PDMS master template, and a UV-replicated grating pattern was formed within the cured optical epoxy layer on the glass substrate (Figure 3c,d).…”

“…Since our original report on embedding multiple small-area transparent diffraction gratings produced by lift-off photolithography into various solar windows [28], several alternative (and more cost-effective) technical approaches to the manufacture of microstructured diffractive elements have been trialed. We recently explored the energy-harvesting potential of transparent gratings produced by pattern replication processes based on soft lithography techniques [32][33][34][35]. In this paper, we report on the process details and the principal results achieved with diffraction-assisted glass-based solar concentrator windows, 200 mm × 200 mm in size, in the subsequent sections.…”