Zhenpeng Li 1 , Zheng Zhou 2 , Shannon Armstrong 2 , Eric Baer 2 , D.R. Paul 1 , Christopher J. Ellison 1 1 McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 2 Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106 Background and Motivation Viscosity Modification Characterization of Multilayer Films Acknowledgements The Ellison Group • Dr. Dustin Janes The Paul Group • Dr. Rajkiran Tiwari The Freeman Group Multilayer Film from Coextrusion Challenges Conclusions Liquid Crystalline Polymer Multilayer Film The viscosity of LCP is dramatically increased by reacting with Heloxy without affecting its unique liquid crystal structure. The quality of multilayer films was significantly improved. LCP chain aligns perpendicular to extrusion direction with ‘log-rolling’ effect. The gas permeability of LCP thin film is dramatically decreased due to nano- confinement. Liquid Crystalline Polymer Multilayer Films for High Barrier Materials Materials and Experiments Rheological Properties Modification Orientation of LCP in Multilayer Films 100 nm A B ABA Feedblock Layer Multipliers Surface layer A B Surface layer … Crystal morphology under confinement Enhanced barrier property by confinement Tortuous Diffusion Pathway Permeability decreased by 2 orders of magnitude Wang H, Freeman B et al. Science 2009, 323, 757. High barrier properties Good mechanical properties High solvent resistance Liquid Crystalline polymer (LCP) nano scale micro scale LCP multilayer film Enhance barrier properties of LCP (Super high barrier film) Decrease the price of the membrane products The viscosities of the two components should match in order to make high quality multilayer films Objective: Enhance the viscosity of LCP to make high quality multilayer films Preserve the intrinsic liquid crystal structures after the rheological modification Microcompounder Viscosity of V400p is increased by nearly 20x after reacting with Heloxy The liquid crystal structure is not disturbed by the modification The viscosity of Vectra V400p is dramatically increased, making it possible to match the viscosity of other conventional polymers. The processing window is chosen at the temperature where the viscosities of V400p matches that of the PP-g-MA d 1 d 2 The LCP chain is oriented perpendicular to the extrusion direction due to a ‘log- rolling’ effect. Multilayer coextrusion Z Li, et al. Polymer 2014 Improved Layer Quality by Viscosity Modification Consecutive cross-section SEM images showing the layer integrity of the modified V400p/PP multilayer films over large distances Cross-section SEM images of the neat V400p and modified V400p/PP multilayer films Overall quality of multilayer films Permeability of LCP Thin Films Optically transparent Mechanically flexible Deposition Spreading Thinning Drying Spin coating process: powerful to make nano scale thin polymer films Chemically and thermally inert Cost effective Next generation see through packaging materials