pps proceeding - Abstract Preview
pps proceeding
Symposium: S10 - Injection Molding
Oral Presentation
 
 

Rapid hot embossing of polymer microstructures with high aspect ratios using carbide-bonded graphene coating on silicon stampers

Xie Pengcheng (1), Cabrera Eusebio Duarte (2), Zhang Panpan (1), Yen Ying-Chieh (3), He Peng (2), Gallego-Perez Daniel (4), Chang Lingqian (4), Yi Allen (2), Castro Jose (2), Lee L.James (3)*

(1) College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology - Beijing - China, (2) Department of Integrated Systems Engineering, The Ohio State University - Ohio - USA, (3) Department of Chemical and Biomolecular Engineering, The Ohio State University - Ohio - USA, (4) Center for Affordable Nanoengineering of Polymeric Biomedical Devices, The Ohio State University - Ohio - USA

Hot embossing is a low-cost and flexible process for the fabrication of polymer products with microscale features on the surface. However, the cycle time is often very long, not suitable for high throughout replication. This is because both the embossing stamper and the polymer substrate need to be heated above the glass transition temperature Tg of polymer materials before and then cooled to below Tg after embossing. In this study, we present a new rapid embossing system utilizing a novel carbide-bonded graphene coating on silicon stampers to implement rapid heating and cooling. The graphene layer is highly electrically and thermally conductive, where a ~45 nm thick coating layer on silicon wafer surface could reach an electrical conductivity of 1.98×104 S/m. Direct current with a relatively low voltage could be applied on the graphene layer to achieve locally heating. As a result, the contact surface temperature of the stamper and the polymer substrate may quickly reach >Tg within tens of seconds for rapid embossing of microstructures. Since the graphene coating is very thin, the stamp surface can be cooled rapidly after embossing to keep the cycle time very short. Furthermore, the graphene coating layer on silicon stamper exhibits excellent surface smoothness and low frication coefficient with a Ra value around 4.5 nm and a surface friction coefficient around 0.029 (vs. 0.076 for Si wafer). For this reason, carbide-bonded graphene coating could significantly facilitate de-embossing, a critical and challenging step for replication of microstructures with high aspect ratios. We will present our embossing results for an optical device and a microfluidics device using PC and PMMA respectively.