The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Thin Al2O3 Barrier Coatings Grown on Bio-Based Packaging Materials by Atomic Layer Deposition

Terhi Hirvikorpi

Doctoral dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Aalto University School of Chemical Technology for public examination and debate in Room 26 at Dipoli Congress Centre (Espoo, Finland) on the 18th of November 2011 at 12 noon.

Overview in PDF format (ISBN 978-951-38-7751-4)   [1677 KB]
VTT Publications 770, ISSN 1455-0849

Dissertation is also available in print (ISBN 978-951-38-7750-7)
Copyright © 2011 VTT Technical Research Centre of Finland
VTT Publications 770, ISSN 1235-0621
VTT-PUBS-770

Abstract

Growing environmental concerns related to the use of synthetic non-biodegradable polymers in the packaging industry have led to the need for new, especially bio-based, materials. Currently, petroleum-based synthetic polymers are widely used due to their relatively low cost and high performance. Biodegradable plastics and fibre-based materials have been proposed as a solution to the waste problems related to these synthetic polymers. Fibre-based packaging materials have many advantages over their non-biodegradable competitors, such as stiffness vs. weight ratio and recyclability. However, poor barrier properties and sensitivity to moisture are the main challenges restricting their use. Application of a thin coating layer is one way to overcome these problems and to improve the barrier properties of such materials.

Atomic layer deposition (ALD) is a well suited technique for depositing thin inorganic coatings onto temperature-sensitive materials such as polymer-coated boards and papers and polymer films. In the present work, thin and highly uniform Al2O3 coatings were deposited at relatively low temperatures of 80, 100 and 130 °C onto various bio-based polymeric materials employing the ALD technique. The study demonstrates that a 25-nm-thick ALD-grown Al2O3 coating significantly enhances the oxygen and water vapour barrier performance of these materials. Promising barrier properties were obtained with polylactide-coated board, hemicellulose-coated board as well as various biopolymer (polylactide, pectin and nanofibrillated cellulose) films after coating with a 25-nm-thick Al2O3 layer.

Thin Al2O3 coatings can improve the properties of biopolymers, enabling the use of these renewable polymers in the production of high-performance materials for demanding food and pharmaceutical packaging applications. The future roll-to-roll ALD technology for coating polymers with inorganic thin films will increase the industrial potential of these materials and could lead to further opportunities for their commercialization.

This thesis consists of an overview and of the following 6 publications:

  1. T. Hirvikorpi, M. Vähä-Nissi, A. Harlin and M. Karppinen, Comparison of some coating techniques to fabricate barrier layers on packaging materials, Thin Solid Films 518 (2010) 5463-5466. © 2010 Elsevier. By permission.
  2. T. Hirvikorpi, M. Vähä-Nissi, T. Mustonen, E. Iiskola and M. Karppinen, Atomic layer deposited aluminum oxide barrier coatings for packaging materials, Thin Solid Films 518 (2010) 2654-2658. © 2009 Elsevier. By permission.
  3. T. Hirvikorpi, M. Vähä-Nissi, J. Nikkola, A. Harlin and M. Karppinen, Thin Al2O3 barrier coatings onto temperature-sensitive packaging materials by atomic layer deposition, Surface and Coatings Technology, 205 (2011) 5088-5092. © 2011 Elsevier. By permission.
  4. T. Hirvikorpi, M. Vähä-Nissi, A. Harlin, J. Marles, V. Miikkulainen and M. Karppinen, Effect of corona pre-treatment on the performance of gas barrier layers applied by atomic layer deposition onto polymer-coated paperboard, Applied Surface Science 257 (2010) 736-740. © 2010 Elsevier. By permission.
  5. T. Hirvikorpi, M. Vähä-Nissi, J. Vartiainen, P. Penttilä, J. Nikkola, A. Harlin, R. Serimaa and M. Karppinen, Effect of heat-treatment on the performance of gas barrier layers applied by atomic layer deposition onto polymer-coated paperboard, Journal of Applied Polymer Science 122 (2011) 2221-2227. © 2011 Wiley Periodicals. By permission.
  6. T. Hirvikorpi, M. Vähä-Nissi, A. Harlin, M. Salomäki, S. Areva, J.T. Korhonen and M. Karppinen, Enhanced water vapor barrier properties for biopolymer films by polyelectrolyte multilayer and atomic layer deposited Al2O3 double-coating, Applied Surface Science 257 (2011) 9451-9454. © 2011 Elsevier. By permission.

Keywords: atomic layer deposition, aluminium oxide, thin film, barrier, biopolymer, packaging material

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© 2011 Aalto University

Last update 2011-11-21