Violin Varnishes: Microstructure and Nanomechanical Analysis

Marianne Odlyha; Jeannette J Lucejko; Anna Lluveras-Tenorio; Francesca di Girolamo; Stephen Hudziak; Adam Strange; Alexandra Bridarolli; Laurent Bozec; Maria Perla Colombini

doi:10.3390/molecules27196378

Violin Varnishes: Microstructure and Nanomechanical Analysis

Molecules. 2022 Sep 27;27(19):6378. doi: 10.3390/molecules27196378.

Authors

Affiliations

¹ Department of Biological Sciences, Birkbeck, University of London, London WC1E 7HX, UK.
² Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, 56127 Pisa, Italy.
³ Department of Electronic and Electrical Engineering, University College London, London WC1E 6BT, UK.
⁴ Eastman Dental Institute, University College London, London WC1E 6DG, UK.
⁵ Getty Conservation Institute, 1200 Getty Center Drive, Suite 700, Los Angeles, CA 90049, USA.
⁶ Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada.

Abstract

The aim of the current work is twofold: to demonstrate the application of in situ non-invasive imaging by portable atomic force microscopy (AFM) on the surfaces of a violin and to integrate compositional and mechanical analysis at the nano scale level on model samples of varnished wood. These samples were prepared according to traditional recipes by an Italian lute-maker family well practised in the art. Samples of oil and spirit-based varnishes on maple wood, naturally and accelerated light aged, were studied. AFM was used to measure the nanomechanical properties of the model samples and established that the spirit-based varnish was stiffer than the oil-based. Synchrotron radiation micro- Fourier Transform Infra-red analysis of the layer structure revealed that stiffer spirit-based varnish showed less penetration into the wood than the oil-based. Further PeakForce Quantitative Nanomechanical Mapping (QNM) demonstrated a difference in adhesion values between the oil- and spirit-based samples.

Keywords: AFM; SR micro-FTIR; in situ imaging; nanomechanics; violin.

MeSH terms

Microscopy, Atomic Force* / methods

Grants and funding

The work benefitted from the outcomes of previous projects including EC 6th & 7th Framework DGXII “Protection & Conservation of European Cultural Heritage”, PROPAINT and 7th Framework projects MEMORI, NANOFORART FP7 project, and participation in WoodMusICK FPS COST action FP1302. The Authors would also like to thank University College London Impact Award and SEAHA for the student funding support. Part of this research was supported by Associazione Liutaria Italiana ALI and the project PRIN 2010–2011: “Sustainability in cultural heritage: from diagnosis to the development of innovative systems for consolidation, cleaning and protection”.