Experimental and theoretical UV/Vis-IR-THz spectroscopies for diagnostic studies of ancient paper - Progetto ADAMO
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Experimental and theoretical UV/Vis-IR-THz spectroscopies
for diagnostic studies of ancient paper
Mauro Missori1*, Adriano Mosca Conte1,2 Conte, Olivia Pulci2
1Istituto dei Sistemi Complessi – CNR, Unità Sapienza, Rome, Italy
2Dipartimento di Fisica, Università di Roma Tor Vergata, Rome, Italy
(*) e-mail: mauro.missori@isc.cnr.it
Outline
Brief description of ancient paper degradation
UV/Vis spectroscopy: measurement of chromophores concentration
IR spectroscopy for the assessment of oxidative degradation of cellulose
THz spectroscopy for the study of supermolecular structure of cellulose
2/15
Degradation of paper arteworks
Leonardo da Vinci’s self-portrait (circa 1510)
Codex on the Flight of Birds (circa 1505)
4v 11v
Front Back
Images acquired in 2012
Diana Scultori «Le Nozze di Psiche» (1613)
3/15
L. Micheli, C. Mazzuca et al., Microchemical Journal 138, 369-378 (2018)
Degradation at the molecular scale
H
External O
temperature Internal
humidity C byproducts
radiations impurities
microorganisms
oxidation
hydrolysis
Development of acidic
byproducts (pH)
UV-Vis active oxidized groups
Mechanical and morphological degradation (chromophores) containing carbonyl
(C=O) groups
Variation of optical properties (yellowing)
T. Lojewski, et al., Carbohydrate Polymers 82, 370 (2010). 4/15
S. Zervos, Natural and Accelerated Ageing of Cellulose and Paper: A Literature Review (2010).
Measurement of paper optical response
Whatman® 1
Paper → fibres and voids with sizes > λ
→ optically inhomogeneous medium
→ optical properties are strongly
governed by light scattering
10 mm
Kubelka-Munk theory
Medium described by 2 phenomenological constants: Input
output to radiation
- absorption coefficient K integrating
spectrometer
- scattering coefficient S sphere
proportional to the concentrations (ci) of chromophores
K K (1 R ) 2
i i ci
2 i i S 2 R
S is needed in order to recover K paper
G. Kortum, Reflectance Spectroscopy, Springer-Verlag (1969)
L. Yang, S. J. Miklavcic, J. Opt. Soc. Am. A 22, 9, 1866 (2005) or black backing 5/15
M. Missori et al., Physical Review B 89, 054201 (2014)
UV-Vis results on the Leonardo’s drawings
C4v Diffuse reflectance R∞ Absorption coefficient (cm-1)
modern
(cellulose fibers)
sample
C11v
C2r
Pr1 presence of several chromophores
Pr2 Pv
6/15
Cellulose chromophores theoretical simulation
Density Ground state properties: optimization
Functional of the unitary cell geometry of pristine
Theory (DFT) and oxidized cellulose (monoclinic
crystallographic phase Iβ)
http://www.quantum-espresso.org/
diketone
Visible
Time-Dependent Oxidized groups excited state
DFT properties: dielectric function of
cellulose CHOb
aldehyde
→ UV-Vis absorption spectrum Near UV
http://dp-code.org
ketone
UV
7/15
UV-Vis experimental vs. theoretical spectra
Minimal square Min [(exp(l)-i ai theoi(l))2 ] → ci = (ai / jaj) × 100%
algorithm
diketones
aldehydes
ketones
6.1 mmol/100g cellulose 2 mmol/100g cellulose
8/15
Chromophores concentration reduction in Le Nozze di Psiche (1613)
%
L. Micheli, C. Mazzuca et al., Microchemical Journal 138, 369-378 (2018) 9/15
M. Missori et al., Eur. Phys. J. Plus 134, 99-110 (2019)
Infrared spectroscopy of oxidized groups in cellulose
Near UV-Vis active UV active
K. Ahn et al., Cellulose 26, 1, 429–444 (2019)
Transmission cellulose 99.5%, lignin 0.5% cellulose 100.0%
experiments
Aging at
days 90°C
RH=59%
days
10/15
T. Łojewski et al., Appl Phys A 100, 809–821 (2010)Oxidized groups detection in pure cellulose paper
Label Aging conditions Expected degradation factors Reactor type
D Dry air 90°C Air Drier increasing
C Air at RH=59%, 90°C Air and water vapour Climatic chamber
degradation
V Air at RH=59%, 90°C Air, water vapour, gaseous by-products Closed vial
In collaboration with A. Nucara and M. Ortolani (Physics Dept., Sapienza Univ. of Rome)
Vacuum FT-IR spectrometer (Bruker IFS66v/S) equipped with reflection setup
Spectra after 24 hours under vacuum Difference spectra with unaged
11/15Comparison with theoretical spectra
Formic acid
Taking into account Van der Waals interactions
OH
OH and CH
CH C=O
12/15THz time-domain spectroscopy
THz radiation for non-invasive diagnostics
Negligible ionization power
Penetrates optically opaque materials like painting layers,
paper, plastics ... but no metals …and water !
0.2 1 2 (THz)
THz spectroscopy Indomethacin
(anti-inflammatory drug)
Frequency range 100 GHz - 10 THz (3 cm−1 - 300 cm−1)
Detection and identication of low-energy vibrational modes
Chemical analysis of intermolecular hydrogen bonds
crystalline
Y. Ueno, Analytical Sciences, 24, 185-192 (2008)
C. Ciano et al., IEEE Trans. Terahertz Sci. Technol. 8, 4 (2018)
Clare J. Strachan et al., Chemical Physics Letters 390, 20–24 (2004) 13/15
K. Fukunaga, THz Technology Applied to Cultural Heritage in Practice, Springer, 2016THz time-domain spectroscopy
33 67 100 (cm-1)
Ab-initio low frequency vibrations
2.2 THz
2.7 THz
3.0 THz
Moisture-activated dynamics on crystallite surfaces in cellulose
M. Missori et al., Microchem J 142, 54-61 (2018) 14/15
C. J. Garvey et al. Colloid and Polymer Science 297, 521–527 (2019)Conclusions
Experimental and theoretical spectroscopy as non-destructive
diagnostic method for cultural heritage
Identification and quantification of chromophores in ancient paper
Identification of the IR spectra of oxidized groups in the ageing
process of cellulose
THz diagnostics of ancient paper: influence of water in the low-
frequency vibration of cellulose polymers
15/15People
Theory Paper restoration
Adriano Mosca Conte Olivia Pulci
Simonetta Iannuccelli Silvia Sotgiu Serena Dominijanni
Experiments
Claudia Violante
Arrigo Calzolari
Lorenzo Teodonio
Joanna Łojewska Marco Peccianti
Marco Buongiorno Nardeli 16You can also read
