Modeling the constitutive and frictional behavior of PTFE flexible stamps for nanoimprint lithography

In the present work, the deformation on micro-scale of PTFE flexible stamps for nanoimprint lithography is modeled. This is achieved via a combination of proper models for the constitutive behavior as well as the frictional conditions between the deforming PTFE stamp and the steel tool. The model was verified through an experiment, where a PTFE sheet was deformed by a steel sphere mounted in a tensile test machine. Good agreement between simulations and experimental results is found, both regarding force–displacement and corresponding principal strain measurements. As expected, applying the correct frictional behavior between PTFE and steel on micro-scale is shown to be of major importance in order to accurately simulate the strain field in the deformed PTFE stamp.

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► Modeling the deformation of PTFE flexible stamps for nanoimprint lithography.
► Obtaining a proper constitutive description of PTFE under biaxial stretching based on the Johnson–Cook model.
► Describing correctly the frictional conditions on microscale between the deforming PTFE stamp and the steel tool.
► Strain fields on deformed stamp obtained experimentally and compared with numerical results.