Physicochemistry of Pure Lead(II) Soaps: Crystal Structures, Solid and Liquid Mesophases, and Glass Phases – Crystallographic, Calorimetric, and Pair Distribution Function Analysis

Martínez-Casado, Francisco J.; Rodríguez-Cheda, José A.; Ramos-Riesco, Miguel; Redondo-Yélamos, María Isabel; Cucinotta, Fabio; Fernández-Martı́nez, Alejandro

doi:10.1007/978-3-319-90617-1_13

Cited by 4 publications

(5 citation statements)

References 16 publications

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“…In the two 1941 paintings (Pedernal and A Man from the Desert) painted on pre-primed commercial canvas, lead carboxylates have aggregated and developed into mechanically damaging and visual compromising lead soap protrusions. Analysis by FT-IR showed a broad IR absorption band at 1520 cm −1 suggesting that lead soaps in Georgia O'Keeffe oil paintings are also present in an amorphous state, and GC-MS data indicated that the protrusions contain primarily lead palmitate and lead stearate [8,18,26]. Based on FT-IR data, and the appearance of new soap protrusion in retouched areas we can suggest that lead carboxylates in Georgia O'Keeffe oil paintings will continue to actively form.…”

Section: Discussionmentioning

confidence: 89%

“…Commonly, such soaps remain where they developed initially without any deleterious effect to the surrounding matrix [5]. This observation has led to a significant amount of recent research attempting to address what reactive forces induce metal carboxylate soaps to sometimes undergo phase segregation [6][7][8]. Since their initial discovery [9,10] two decades ago, understanding how, where, and why protrusions occur has become one of the critical research foci in oil painting conservation.…”

Section: Introductionmentioning

confidence: 99%

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The influence of commercial primed canvases in the manifestation of metal soaps protrusions in Georgia O’Keeffe’s oil paintings

2020

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During a routine condition survey in 2007 at the Georgia O’Keeffe Museum in Santa Fe, micro-protrusions were found scattered across the surfaces of the artist’s oil paintings produced between 1920 and 1950. In many of her works, including Pedernal (1941) and A Man from the Desert (1941), lead soaps were found aggregated at the painting surface, forcing the surrounding paint to deform into pin-sized protrusions. The structure and composition of the protrusions was analyzed to determine why they formed. Microsamples were removed from four of O’Keeffe’s paintings and investigated using a combination of SEM–EDX, GC–MS, and FT-IR. The combined GC–MS and FT-IR results indicate that the protrusions contain primarily lead carboxylates. The results obtained for a series of ground samples removed from four different paintings were then compared with samples collected from a commercially pre-primed canvas roll found in the artist’s house in Ghost Ranch, NM. We identified two different types of canvases: i) a commercially pre-primed canvas and ii) artist primed canvas. This commercially pre-primed canvas roll has a similar morphology to the ground layers in her paintings that contain protrusions additionally these grounds were found to contain an excess of free fatty acids and metal carboxylates (lead soaps) based on a comparison to canvases the artist primed herself. Based on the analytical results from the four paintings and the commercial pre-primed canvas, we concluded that the artist’s use of this particular commercially pre-primed canvas between 1920 and 1950 play an important role in the observed micro-protrusions.

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Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

The influence of commercial primed canvases in the manifestation of metal soaps protrusions in Georgia O’Keeffe’s oil paintings

2020

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“…The trends in antisymmetric and symmetric carboxylate maxima for various sodium, calcium, and zinc soaps are shown in Figure S4 . A significant feature of the carboxylate bands is the separation Δ ν between the antisymmetric and symmetric peaks, considered to depend on factors such as the type of metal, the ligand, and the coordination type and denticity [ 157 , 158 ], the packing of chains [ 158 , 159 , 160 , 161 ], as well as the molecular environment (solvent, or other materials in the molecular environment) [ 73 , 160 ]. As shown in Figure S4 (values drawn from spectra in Figure 4 , Figure 5 , and Figure 7 ), the Δ ν value in the lower-symmetry sodium soaps is generally expected to be ~137 cm −1 , while for the higher-symmetry calcium and zinc, this is expected to be higher at 142–144 cm −1 [ 158 ].…”

Section: Resultsmentioning

confidence: 99%

Fatty Acids and Their Metal Salts: A Review of Their Infrared Spectra in Light of Their Presence in Cultural Heritage

2021

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In a cultural heritage context, fatty acids are usually found as breakdown products of lipid-containing organic remains in archaeological findings, binders in aged oil paintings, and additives in modern art-related materials. They may further interact with the ionic environment transforming into metal soaps, a process that has been recognized as a threat in aged paintings but has received less attention in archaeological objects. The investigation of the above related categories of materials with infrared spectroscopy can provide an overall picture of the organic components’ identity and demonstrate their condition and prehistory. The capability of investigating and distinguishing fatty acids and their metal soaps through their rich infrared features, such as the acidic carbonyl, the carboxylate shifts, the variable splits of alkyl chain stretching, bending, twisting, wagging, and rocking vibrations, as well as the hydroxyl peak envelopes and acid dimer bands, allows for their direct detailed characterization. This paper reviews the infrared spectra of selected saturated fatty monoacids and diacids, and their corresponding sodium, calcium, and zinc salts and, supported by newly recorded data, highlights the significance of their spectroscopic features.

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“…The structuring of lamellar phases of lead soaps under oscillatory shear significantly differed from what has been reported for other lamellar systems. Most studies on lead soaps have focused on the behavior of straight saturated chains, without considering the potential effect of unsaturation on supramolecular organization [48,49]. Moreover, here, we do not consider pure lamellar systems but rather a complex mixture whose constituents have opposite behaviors.…”

Section: Oscillatory Shearmentioning

confidence: 99%

Rheo-SAXS characterization of lead-treated oils: Understanding the influence of lead driers on artistic oil paint’s flow properties

Laporte

Ducouret

Gobeaux

et al. 2023

Journal of Colloid and Interface Science

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Physicochemistry of Pure Lead(II) Soaps: Crystal Structures, Solid and Liquid Mesophases, and Glass Phases – Crystallographic, Calorimetric, and Pair Distribution Function Analysis

Cited by 4 publications

References 16 publications

The influence of commercial primed canvases in the manifestation of metal soaps protrusions in Georgia O’Keeffe’s oil paintings

The influence of commercial primed canvases in the manifestation of metal soaps protrusions in Georgia O’Keeffe’s oil paintings

Fatty Acids and Their Metal Salts: A Review of Their Infrared Spectra in Light of Their Presence in Cultural Heritage

Rheo-SAXS characterization of lead-treated oils: Understanding the influence of lead driers on artistic oil paint’s flow properties

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