Collapse of elastomeric elements used for pattern transfer in soft lithography is studied through experimental measurements and theoretical modeling. The objective is to identify the driving force for such collapse. Two potential driving forces, the self-weight of the stamp and the interfacial adhesion, are investigated. An idealized configuration of periodic rectangular grooves and flat punches is considered. Experimental observations demonstrate that groove collapse occurs regardless of whether the gravitational force promotes or suppresses such collapse, indicating that self-weight is not the driving force. On the other hand, model predictions based on the postulation that interfacial adhesion is the driving force exhibit excellent agreement with the experimentally measured collapse behavior. The interfacial adhesion energy is also evaluated by matching an adhesion parameter in the model with the experimental data.
Bibliographical noteFunding Information:
The authors acknowledge the financial support from the NSF through Nano-CEMMS (Grant No. DMI 03-28162) at the University of Illinois. Two of the authors (K. J. H. and J. M. F.) also acknowledge the financial support from DOD and NSF through an REU site (Grant No. EEC 03-54102) in the Department of Theoretical and Applied Mechanics at the University of Illinois.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)