title: Roll-to-Roll Continuous Manufacturing Multifunctional Nanocomposites by Electric-Field-Assisted "Z" Direction Alignment of Graphite Flakes in Poly(dimethylsiloxane).
abstract: A roll-to-roll continuous process was developed to manufacture large-scale multifunctional poly(dimethylsiloxane) (PDMS) films embedded with thickness direction ("Z" direction) aligned graphite nanoparticles by application of electric field. The kinetics of particle "Z" alignment and chain formation was studied by tracking the real-time change of optical light transmission through film thickness direction. Benefiting from the anisotropic structure of aligned particle chains, the electrical and thermal properties of the nanocomposites were dramatically enhanced through the thickness direction as compared to those of the nanocomposites containing the same particle loading without electrical field alignment. With 5 vol % graphite loading, 250 times higher electrical conductivity, 43 times higher dielectric permittivity, and 1.5 times higher thermal conductivity was achieved in the film thickness direction after the particles were aligned under electrical field. Moreover, the aligned nanocomposites with merely 2 vol % graphite particles exhibit even higher electric conductivity and dielectric permittivity than those of the nonaligned nanocomposites at random percolation threshold (10 vol % particles), as the "electric-field-directed" percolation threshold concentration is substantially decreased using this process. As the graphite loading increases to 20 vol %, the aligned nanocomposites exhibit thermal conductivity as high as 6.05 W/m·K, which is 35 times the thermal conductivity of pure matrix. This roll-to-roll electric field continuous process provides a simple, low-cost, and commercially viable method to manufacture multifunctional nanocomposites for applications as embedded capacitor, electromagnetic (EM) shielding, and thermal interface materials.
authors.affiliation: Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States.
authors.forename: Yuanhao
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States.|Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of Science & Technology , Qingdao 266042, China.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States.
authors.forename: Enmin
authors.initials: E
authors.lastname: Wang
authors.affiliation: Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States.|School of Materials Engineering, School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Miko
authors.identifier: http://orcid.org/0000-0001-9128-7833
authors.initials: M
authors.lastname: Cakmak
keywords: multifunctional; nanoparticle alignment; roll-to-roll