ERC-Small Business: Micropatterning of Film Extrusion Die Surfaces

Clemson University, Clemson SC

Investigators

Abstract

This is a collaboration between the Engineering Research Center (ERC) for Advanced Engineering Fiber and Films (CAEFF) at Clemson University and Hoowaki LLC. CAEFF is a graduated, self-sustaining ERC (EEC-9731680) that continues to conduct systems-level research and educate students on advanced fibers and films. Hoowaki LLC is a small business company that has completed a Phase I SBIR (Grant No. 0945386) and developed unique expertise in surface microstructuring of metal molds. The vision of the Hoowaki-CAEFF Clemson team is to translate research and test-beds developed in CAEFF into commercial products being developed by Hoowaki LLC to radically modify surface properties of extruded polymeric articles to create large markets and to realize important societal benefits. The Hoowaki-CAEFF team proposes to develop micropaterned extrusion dies to attain micron- and submicron-level (nano-level) features on film surfaces. Hoowaki researchers have demonstrated superhydrophobic microstructures of polymers using 3-D patterns on mold surfaces used in batch processing. The proposed program will result in extruded films with desired micro-patterns and functional performance (such as superhydrophobicity) using the continuous, high-volume extrusion process, which is well suited for scale-up to commercial processes. Dies developed by Hoowaki will be used by CAEFF researchers in extrusion test-beds developed under the auspices of the ERC program. The proposal will draw upon CAEFF's custom-designed single- and multi-layer polymer film extrusion test-beds equipped with real-time Raman spectroscopy and x-ray diffraction capabilities. Extensive rheological and analytical instrumentation, also available in CAEFF, will be used for flow and microstructure measurements. CAEFF-Hoowaki team will complement these experimental studies with computer modeling using FiSim software, which was also developed under the auspices of the ERC program. Validated computer modeling predictions using accurate viscoelastic constitutive equations will systematically guide the micropatterning geometries for attaining superhydrophobic microtexture and reduced friction properties. Broader Impact The Hoowaki R&D Manager and CAEFF Director will mentor a post-doctoral research associate and a graduate, who in turn will mentor an undergraduate student. Thus, integration of research and education will be accomplished to ensure training of research personnel for U.S. competitiveness. Hoowaki personnel will also advise post-doctoral, graduate, and undergraduate students on aspects of product-development and entrepreneurship. This work is expected to benefit society and U.S. consumers by improving packaging films to improve cleanliness for improved hygiene. The micro-patterned dies are expected to lead to improved energy efficiency of film extrusion due to improved production rates. In addition, reduction of fluoropolymer coatings, in favor of the microtexture to enhance superhydrophobicity, will provide significant environmental benefits.