Posted in | News | Nanomaterials | Graphene

Nanocomposites Help to Continue the Cultural Legacy of Murals

In an article recently published in the open-access journal ACS Omega, researchers described a unique technique for protecting murals with graphene-based nanomaterials.

Nanocomposites Help to Continue the Cultural Legacy of Murals

Study: Polyacrylic Acid-Functionalized Graphene@Ca(OH)2 Nanocomposites for Mural Protection. Image Credit: salajean/

The team developed a facile and cost-effective aqueous process to strategically synthesize a polyacrylic acid-functionalized graphene/nano-Ca(OH)2 (PAAG@Ca(OH)2) material.

What are Murals?

Murals are an essential component of humanity's rich cultural legacy. They are, however, prone to serious damage over time, such as hollowing, fungus damage, flaking, and cracking. As a result, the development of mural reinforcing materials is becoming increasingly important for cultural heritage preservation.

Mural reinforcing materials are primarily split into two categories: inorganic and organic.

The use of inorganic materials will inevitably affect the aqueous solution in the mural, resulting in the crystallization of the soluble salts and poor permeability. Hence, organic acrylic polymers have recently been used to strengthen murals due to their outstanding adhesion, permeation, and transparency.

However, after heat oxidation and optical irradiation, organic polymer materials develop a noticeable aging problem, resulting in mechanical strength reduction.


Importance of Graphene Nanomaterials in Murals

The distinctive nanoparticle size and physicochemical features of diverse nanomaterials have gained attention in protecting heritage. Graphene's unique structure and composition have led to its integrtion across many sectors, yet its involvement in historical preservation is small, especially in mural applications.

Polyacrylic Acid-Functionalized Reduced Graphene Oxide (PAAG)@Ca(OH)2 Nanocomposite for Protection of Murals

In the present study polyacrylic acid-functionalized graphene was combined with nano-Ca(OH)2 to form a PAAG@Ca(OH)2 nanocomposite. The PAAG@Ca(OH)2 nanocomposites were manufactured using a cost-effective, facile, aqueous approach for mural protection using polyacrylic, acid-functionalized graphene.

The Hummers method was used to create graphite oxides from natural graphite powder to manufacture graphene oxide (GO). To better comprehend the PAAG@Ca(OH)2 nanocomposites, a high-resolution transmission electron microscopy (HRTEM) image was examined.

The (101) crystal plane of the Ca(OH)2 phase was assigned a lattice distance of 0.263 nm, which was compatible with the SAED pattern of the nanocomposites. The elemental mapping and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of the PAAG@Ca(OH)2 nanocomposites were also evaluated.

The elemental contents of the produced PAAG@Ca(OH)2 nanocomposite were measured by using energy dispersive X-Ray (EDX) spectroscopy and the crystal structure of the PAAG@Ca(OH)2 nanocomposites was studied using X-Ray diffraction (XRD) measurements. The chemical state of the elements in the PAAG@Ca(OH)2 nanocomposites was determined using X-Ray photoelectron spectroscopy (XPS) measurements.

The effect of PAAG@Ca(OH)2 and AC33 on the mural was assessed using chromatic aberration measurements, while the pore size distribution and porosity were measured using a mercury porosimeter. The "Scotch tape test" (STT) was also used to assess the PAAG@Ca(OH)2 bonding strength.

TEM image (A), HRTEM image (B), SAED pattern (C), HAADF–STEM image (D), and elemental mapping images (E–H) of PAAG@Ca(OH)2. © Gu, W., et al (2022)

Research Findings

According to the simulated tests, the nanocomposite PAAG@Ca(OH)2 had higher porosity, suitable hydrophilicity, stronger adsorption, and superior permeability than the commercial AC33 sample.

In the XPS survey spectra of PAAG@Ca(OH)2, three elements - C, O, and Ca - were found. PAAG@Ca(OH)2 had ΔE values less than 5, whereas AC33 had ΔE values more than 5. After being reinforced with PAAG@Ca(OH)2, the hue of simulated samples was not altered much. After reinforcement with AC33, the porosity decreased to 53.2182%, whereas after reinforcement with PAAG@Ca(OH)2, the porosity increased to 54.10%.

The weight loss of the untreated sample, which was not covered with any reinforcing substance, was 3.21 ± 0.5 mg cm-2. Of the AC33-consolidated simulated samples, it was reported to be 1.54 ± 0.5 mg cm-2. The weight loss for the simulated samples consolidated with the PAAG@Ca(OH)2 nanohybrids, on the other hand, was 0.71 ± 0.3 mg cm-2.

PAAG@Ca(OH)2 had a lower moisture exchange effect on the mural, which could be employed to reinforce the pigment layer. The Raman peaks of the AC33 were around 1457 and 1683 per centimeter for the as-prepared AC33 consolidated mural sample, and the intensity appeared from 0 to 200 micrometer and dropped from 200 to 350 micrometer.


In conclusion, this study elucidated the potential of PAAG@Ca(OH)2 nanocomposite as a reinforcement material for mural conservation. The PAAG@Ca(OH)2 manufactured by the researchers could easily capture and store CO2 in the ambient atmosphere due to graphene's huge specific surface area. In addition, simulated experiments showed that the as-prepared PAAG@Ca(OH)2 nanocomposite exhibited strong adsorption, adequate hydrophilicity, and great adherence to mural pigments, making it a potential option for mural consolidation.

The authors emphasized that the PAAG@Ca(OH)2 nanocomposite outperformed the AC33 in terms of conservation efficiency, demonstrating an important application of graphene as a protective material for mural reinforcement.


Gu, W., Wei, Y., Liu, B., et al. (2022) Polyacrylic Acid-Functionalized Graphene@Ca(OH)2 Nanocomposites for Mural Protection. ACS Omega

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

Surbhi Jain

Written by

Surbhi Jain

Surbhi Jain is a freelance Technical writer based in Delhi, India. She holds a Ph.D. in Physics from the University of Delhi and has participated in several scientific, cultural, and sports events. Her academic background is in Material Science research with a specialization in the development of optical devices and sensors. She has extensive experience in content writing, editing, experimental data analysis, and project management and has published 7 research papers in Scopus-indexed journals and filed 2 Indian patents based on her research work. She is passionate about reading, writing, research, and technology, and enjoys cooking, acting, gardening, and sports.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Jain, Surbhi. (2022, April 07). Nanocomposites Help to Continue the Cultural Legacy of Murals. AZoNano. Retrieved on September 30, 2023 from

  • MLA

    Jain, Surbhi. "Nanocomposites Help to Continue the Cultural Legacy of Murals". AZoNano. 30 September 2023. <>.

  • Chicago

    Jain, Surbhi. "Nanocomposites Help to Continue the Cultural Legacy of Murals". AZoNano. (accessed September 30, 2023).

  • Harvard

    Jain, Surbhi. 2022. Nanocomposites Help to Continue the Cultural Legacy of Murals. AZoNano, viewed 30 September 2023,

Tell Us What You Think

Do you have a review, update or anything you would like to add to this news story?

Leave your feedback
Your comment type