The use of wooden façades as an element of charm and aesthetics is becoming increasingly popular on newly built or renovated houses. In this role, expectations for wooden façades are high regarding longevity, resistance to weather and retention of aesthetic properties. Non-thermal plasma treatments offer ways to improve all of these features. In the presentation, a brief overview on atmospheric non-thermal plasmas, the availability of the respective technologies, as well as the benefits and limitations of these will be given. Selected examples for all available technologies will be presented to highlight the forms of implementation, typical applications, and the resulting improvements and functionalities. Dr. Sebastian Dahle is working on the position of a scientific associate and as an assistant professor at the Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana. Further, he leads the Plasma Center at the Biotechnical Faculty, which was established in 2019. His research activities include applications of non-thermal plasmas for surface functionalization, enhanced coating performance, improvement of adhesion, multi-material composites and for plasma deposition. A particular focus of his research lies with the use and improvement of bio-based materials and bio-based composites. Moreover, his research includes plasma applications for processing and cleaning of various gases as well as the development of open plasma equipment.

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Sebastian Dahle
Opportunities of non-thermal plasma applications
on wooden façades
Ljubljana, 21. 7. 2021

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
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PLASMA TECHNOLOGY

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
• neutral gas: plasma – ionized gas:
• e.g. in air:
• oxygen ozone, oxygen radicals, i.a.
• O2 O3, O*, O2
-,…
• ➯ chemical reactions
Introduction – Non-thermal plasma
electrical
energy

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Air ionization
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Limit current:
Dielectric barrier discharges
Limit residence time:
Gliding arc jets

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Dielectric barrier discharges
• Tgas ~ 30 °C
• Eelectron ~ 10 eV
• in air at 1000 hPa
Sources:
Image left – Wolkenhauer et al. https://doi.org/10.1016/j.ijadhadh.2007.11.001
Image right – https://www.ist.fraunhofer.de/de/leistungsangebot/oberflaechenmodifikation.html
Plasma parameters after: https://doi.org/10.1023/A:1022470901385

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Surface barrier discharges
• Tgas ~ 30 °C
• Eelectron ~ 10 eV
• in air at 1000 hPa
Sources:
TL: http://www.roplass.cz/products/product/rps400-for-roll-to-roll/
BL&M: Plasma Center, University of Ljubljana
TR: Odrášková et al. (2008) http://dx.doi.org/10.1007/s11090-007-9117-8
BR: Homola et al. (2013) http://dx.doi.org/10.1007/s11090-013-9467-3

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Air plasma chemistry
Sources:
Penetrante et al. Plasma Sources Sci. Technol. 6 (1997) 251-259

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Corona discharges
• Tgas ~ 30 °C
• Eelectron ~ 10 eV
• in air at 1000 hPa
Sources:
Image left - http://doi.org/10.5772/19129
Image right – https://www.vetaphone.com/wp-content/uploads/2019/03/corona-treatment.jpg
Plasma parameters after: https://doi.org/10.1002/ppap.200400046

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Plasma jets
• Tgas ~ 15 – 300 °C
• Eelectron ~ 2 eV
• in air at 1000 hPa
Sources:
Image left – https://interreg-icap.eu/wp-content/uploads/2017/08/Atmospheric-and-Low-Pressure-Plasma-treatments_a-comparison.pdf
Image right – https://www.ist.fraunhofer.de/de/leistungsangebot/anlagen_und_komponenten/disc-jet.html
Tgas – https://www.plasmatreat.com/faq.html
Eelectron – https://doi.org/10.1063/1.4986296

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
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PLASMA APPLICATIONS

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Air plasmas on wood
Sources:
Žigon et al. (2018) HF 72:979-991, doi: 10.1515/hf-2017-0207

12. https://mscafacade.com/
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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Reduced water uptake through stain
Water uptake through stain reduced due to plasma pretreatment by
(3-day immersion)
• 15% on MDF
• 51% on beech
• 68% on spruce
• 11% on OSB
Sources:
Dahle et al. (2020) 51st IRG WP conference

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Color stability of stained spruce in AAW
• Colour changes
after weathering
somewhat lower
on plasma pre-
treated specimen
• Higher gloss for
PT specimen
both, before and
after weathering
Sources:
Dahle et al. (2020) 51st IRG WP conference
Weathering
Time / h
NT PTC
ΔE ΔL* Δa* Δb* ΔE ΔL* Δa* Δb*
10 1.55 -1.65 -0.51 -1.16 1.28 -1.01 -0.99 -1.69
50 1.81 -1.88 -0.43 -1.50 1.69 -1.38 -1.25 -2.16
63 2.07 -2.19 -0.72 -1.70 1.66 -1.44 -1.25 -1.95

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Reduced cracking & less infections with biotic factors
Sources:
Dahle et al. (2021) Cellulose doi: 10.1007/s10570-021-04014-2

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Enhanced mechanical stability
Sources:
Left: Avramidis et al. (2011) https://doi.org/10.1007/s00107-010-0429-7
Right: Wascher et al. (2017) https://doi.org/10.1016/j.ijadhadh.2017.07.003

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Example: Wood bonding with metals
Wood/
/Wood
Wood/
/Steel
Wood/
/Alu
Sources:
Žigon et al. (2020) Cellulose 27:6411-6424, doi: 10.1007/s10570-020-03212-8

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Plasma deposition
 Utilization of precursors, e.g.
 Silicones (HMDSO, TEOS)
 Fluorocarbons (C4F8)
 Hydrocarbons (propylene)
 Supply of precursors
 In working gas mixture
 Via nebulizer
 As aerosole particles
 Through plasma jet

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
Plasma – a jack of all trades?
Variations between Economic feasibility compared
species and applications to conventional techniques
Case by case optimization and decision!

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
CONCLUSIONS
Plasma treatments…
Are industrially well-established and scalable
Offer various opportunities for wood technology & wood protection
Applications require a case-by-case approach

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FAÇADE project -- Grant Agreement #898179 -- H2020-MSCA-IF-2019; InnoRenew project -- EU Framework Programme for Research and Innovation (H2020 WIDESPREAD-
2-Teaming #739574) and the Republic of Slovenia (investment funding from the Republic of Slovenia and the EU’s European Regional Development Fund)
10.5281/zenodo.5118534