Harnessing natural monoterpenes: cold plasma polymerization of citronellol

Abstract

This study presents the cold plasma polymerization of citronellol, a natural monoterpene, as a route to obtain antibacterial polymeric films. A 10 µL volume of citronellol was polymerized under argon plasma at 100 Pa, yielding a solid film (Pcit). SEM analysis revealed a heterogeneous, branched surface with a roughness Ra of 7.53 ± 2.19 µm and Rz of 50.57 ± 24.26 µm. Water contact angle measurements indicated moderate hydrophilicity (62°). XPS and FTIR analyses confirmed the presence of oxygen-containing functional groups, while OES detected reactive carbon- and oxygen-containing species generated during plasma operation. Hemolysis tests showed excellent blood compatibility (<5%), and antimicrobial assays revealed inhibition zones of 12 ± 1 mm for E. coli and 10 ± 1 mm for S. aureus. Overall, these results indicate that plasma-polymerized citronellol yields functional surfaces with promising potential for biomedical and antibacterial applications.

Keywords:
citronellol; cold plasma; green chemistry; monoterpenes; polymerization

1. Introduction

Plasma-based processes have become an effective alternative for the synthesis and surface deposition of organic thin films, particularly in cases where conventional catalytic polymerization routes are limited by catalyst deactivation, solvent use, or incompatibility with temperature-sensitive substrates, especially for the fabrication of functional coatings derived from bio-based organic monomers[¹,²]. In this context, plasma polymerization enables the activation of organic monomers through energetic species such as electrons, ions, and metastable atoms, leading to the formation of highly crosslinked, solvent-free coatings without the need for external initiators or catalysts[³,⁴]. In recent years, interest in the plasma processing of bio-based monomers has grown significantly, driven by the demand for sustainable materials and functional coatings with intrinsic biological activity[⁴,⁵]. Among these precursors, terpenes and terpenoid compounds derived from essential oils have been extensively explored due to their renewable origin, structural diversity, and the presence of functional groups that can be preserved, to varying extents, during plasma-induced fragmentation[⁶-⁸]. Previous studies have demonstrated the feasibility of plasma-deposited films derived from monoterpenes such as limonene, linalool, carvacrol, and related compounds, yielding amorphous, highly crosslinked polymeric networks with tunable surface chemistry and wettability[³,⁹-¹¹]. Nevertheless, despite these advances, the plasma processing of terpene alcohols remains comparatively underexplored relative to hydrocarbon terpenes, and the structure–property relationships of the resulting materials are still not fully understood[⁵,¹²,¹³]. Citronellol is a naturally occurring monoterpene alcohol found in various aromatic plants and is characterized by a wide range of biologically relevant properties, including antimicrobial, antioxidant, and anti-inflammatory activity[¹⁴-¹⁶].

Although citronellol has been extensively studied in its molecular form, there are only a few reports on its transformation under plasma conditions, and its behavior as a precursor in plasma polymerization processes has not been systematically investigated. In particular, it remains unclear how plasma-generated reactive species influence the fragmentation, recombination, and crosslinking pathways of citronellol, as well as the structural nature of the resulting deposited material[³,¹⁷].

In this work, the cold plasma polymerization of citronellol is investigated using an argon-based plasma system, with emphasis on the formation and characterization of plasma-deposited polymeric thin films, which give rise to a highly crosslinked three-dimensional network of predominantly polymeric nature, distinct from conventional linear polymers. The plasma–monomer interaction mechanisms and their influence on the chemical and morphological characteristics of the resulting material are analyzed, allowing the correlation of plasma conditions with the chemical and structural nature of the formed coatings. To this end, a comprehensive characterization is carried out using scanning electron microscopy, profilometry, water contact angle measurements, optical emission spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. By clarifying the nature of plasma-derived citronellol films and their formation pathways, this study contributes to a more consistent understanding of plasma polymerization of bio-based monomers and expands current knowledge on terpene-derived plasma materials. In contrast to previously investigated terpene precursors such as limonene and carvacrol, citronellol presents a distinct molecular architecture characterized by a primary alcohol functional group and higher polarity, which can influence plasma-induced fragmentation pathways, surface oxidation, and functional group retention. These features are expected to promote the formation of oxygen-containing functionalities and alter nucleation–growth behavior during plasma deposition, potentially affecting both surface chemistry and biological performance. Therefore, investigating citronellol as a plasma precursor provides insight into structure–property relationships within terpene-derived plasma polymers and contributes to understanding how precursor functionality governs film morphology, chemistry, and bioactivity.

2. Materials and Methods

2.1 Plasma polymerization of citronellol

Glass substrates (1 cm in diameter) were cleaned prior to deposition by sequential ultrasonication in acetone, ethanol, and deionized water (10 min each), followed by drying under an air stream. This cleaning procedure was employed to remove organic and particulate contaminants that could interfere with plasma polymerization and film adhesion. For plasma polymerization, 10 µL of citronellol (purity ≥ 95%, Sigma-Aldrich) was deposited onto the cleaned glass substrates and uniformly spread by spin coating using the following sequence: 100 rpm for 15 s, 250 rpm for 30 s, and 100 rpm for 15 s, with 1 s pauses between steps. This procedure ensured a uniform distribution of the monomer before plasma treatment. The substrates were then placed inside a cylindrical glass vessel (1.65 L) equipped with stainless steel caps and a copper wire loop positioned around the body of the vessel; one end of the copper wire was connected to the plasma generator (as shown in Figure 1). The plasma reactor was connected to a 13.56 MHz radio-frequency (RF) generator through an impedance-matching network (AT6 Automatic Matching Network). The system was evacuated using a vacuum pump (Maxima C Plus, Fisher Scientific™), reaching a base pressure of 0.26 Pa prior to gas introduction. The pressure inside the reactor was monitored using a single-channel ACS 2000 controller (Alcatel Vacuum Technology). Plasma polymerization was carried out in an argon atmosphere at an RF power of 50 W, a working pressure of 100 Pa, and a treatment time of 10 min. These parameters were selected based on preliminary experiments and literature reports to ensure plasma stability, effective monomer fragmentation, and the formation of continuous polymeric films while avoiding excessive ablation or over-fragmentation. Under these conditions, reproducible plasma polymerization of citronellol was achieved[¹,³,¹⁸]. After plasma polymerization, plasma-polymerized citronellol (Pcit) films were obtained and characterized. The deposited polymer mass was obtained as the mean value of three independent plasma deposition cycles (n=3) and determined by gravimetric analysis based on the mass difference of the substrates measured before and after deposition.

Figure 1
(a) photographic and schematic; (b) representation of the plasma polymerization system.

2.2 Optical emission spectroscopy (OES)

Reactive species generated by plasma discharges were identified with a fiber-optic spectrometer (Ocean Optics) covering 700–900 nm. Spectral monitoring is conducted at the side of the cold-plasma reactor, with the optical fiber positioned horizontally 1 cm away from the wall.

2.3 X-ray photoelectron spectroscopy (XPS)

The XPS spectra of Pcit were collected on a Fisher Thermo Scientific K-Alpha+ with a monochromatic Al-Kα source (hν = 1486.6 eV; 25 W, 15 kV). Survey spectra used an energy step size of 150 eV and a 1.0 eV resolution. High-resolution C 1s and N 1s scans used a 50 eV step and a 0.1 eV resolution. Atomic percentages of C, N, and O were obtained in triplicate from survey spectra with CasaXPS software. High-resolution spectra were Shirley-background-corrected and deconvoluted in Origin 2019b using Gaussian components (FWHM = 1.35 eV). Binding energies were referenced to the C–C/C–H component at 285.04 eV. Relative sensitivity factors were those provided by CasaXPS.

2.4 Attenuated total reflectance-fourier transform infrared (ATR-FTIR)

A Thermo Scientific Nicolet IS50 ATR-FTIR system was employed to obtain the infrared spectra of Pcit and citronellol. Following the collection of Pcit deposited onto a coverslip, the sample was prepared for FTIR analysis. The spectra were acquired by performing 40 scans at a resolution of 4 cm⁻¹.

2.5 Roughness

3D surface topography of Pcit was measured with a Keyence VR-6100 Series 3D Optical Profilometer, providing high-definition images up to 40× magnification. Roughness parameters were extracted from the generated height maps. Roughness parameters were extracted from surface-based topography measurements performed over representative surface regions (1–2 mm²). Data processing included form removal and standard surface filtering to eliminate macroscopic tilt effects while preserving micrometric features associated with plasma-induced agglomerates. Consequently, the reported roughness values reflect the hierarchical surface morphology arising from localized cluster formation rather than the intrinsic roughness of a uniform thin film.

2.6 Static water contact angle (WCA)

WCA was measured by the sessile-drop method using a ramé-hart goniometer (model 100-00). A 2 μL Milli-Q water droplet was dispensed manually; images were analyzed in ImageJ software. Materials were classified as hydrophobic (WCA ≥ 90°) or hydrophilic (WCA < 90°). Measurements were performed on three independently prepared samples corresponding to distinct plasma deposition cycles.

2.7 Scanning electron microscopy (SEM)

Images of Pcit were captured using a JEOL 6000 Scanning Electron Microscope (SEM). Before SEM analysis, the Pcit samples were mounted on aluminum stubs and coated with a 10 nm silver layer using a plasma sputtering system.

2.8 Hemolysis assay

Prior to the hemolysis assay, the plasma-polymerized citronellol (Pcit) films were gently detached from the substrate using a sterile plastic scraper and subsequently dispersed in Alsever’s solution. The dispersion was assisted by mild ultrasonication (5 min) to obtain a homogeneous suspension without inducing thermal or chemical degradation of the material. The blood compatibility of Pcit was assessed through an in vitro hemolysis assay. Human erythrocytes were washed three times with Alsever’s solution and diluted to 10% (v/v). Aliquots (1500 µL) were incubated with Pcit at 1.0, 2.5, or 5.0 mg/mL in 24-well plates at 37 °C for 1 h with gentle shaking (100 rpm). Alsever’s solution and distilled water served as negative and positive controls, respectively. Following incubation, the samples were centrifuged at 2500 rpm for 4 minutes to separate intact cells from the supernatant. Then, 1000 μL of the supernatant was carefully transferred into a new transparent 24-well plate for absorbance measurement at 415 nm (Synergy HTX; BioTek Instruments). Each condition was run in triplicate. Percent hemolysis was calculated using (Equation 1):

$Hemolysis=\frac{A_{sample}-A_{negativecontrol}}{A_{samplecontrol}-A_{negativecontrol}}\times 100\%$ (1)

2.9 Antimicrobial disk

Antibacterial activity of Pcit was assessed by disk diffusion against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Plates were seeded with 200 μL of a 10⁻³ dilution; a 10 mm Pcit disk was placed centrally. A bare glass coverslip served as the negative control. Plates were incubated at 37 °C for 24 hours, and inhibition halo diameters were measured in millimeters. Each condition was tested and evaluated in triplicate to improve statistical reliability.

3. Results and Discussions

3.1 Plasma polymerization process

The development and scaling of eco-friendly synthesis methods are essential to fully exploit the environmental benefits of renewable monoterpenes (MTs). The literature highlights the transformation of monoterpenes, such as citronellol, into (meth)acrylate monomers, which can be polymerized to obtain materials with tailored properties. Furthermore, various polymerization strategies for monoterpene-derived (meth)acrylates, including radical polymerization and ring-opening polymerization, are extensively discussed. Other research articles also explore potential industrial applications of these polymers, including their use in adhesives, coatings, and biomedical materials. The exploration of plasma from noble gases with a focus on argon is noteworthy due to the presence of metastable species within the argon plasma phase, like Ar*[¹⁹]. These species can potentially modify the reaction dynamics, optimizing the polymerization process in certain contexts. When 10 µL of citronellol was subjected to the specified conditions in section 2.1 over a 10-minute duration, 0.12 ± 0.01 mg of a solid film (plasma polymer; Pcit) was obtained.

3.2 Optical emission spectroscopy

Optical emission spectroscopy (OES) was performed to qualitatively identify the reactive species generated during plasma operation. Figure 2 shows a representative emission spectrum recorded during the plasma polymerization of citronellol in argon within the 700–900 nm range. Several emission lines were detected between 750–880 nm, including dominant argon-related emissions. Characteristic Ar I emission lines were identified at approximately 750.4, 763.5, 811.5, and 852–857 nm, which are attributed to transitions of excited neutral argon, in agreement with the NIST database[²⁰]. These emissions are consistent with electron-impact excitation processes leading to the formation of excited argon species, with only minor contributions from ionized argon (Ar II). Weak and unresolved features observed at lower wavelengths may be associated with carbon-containing fragments generated from partial evaporation and plasma-induced fragmentation of citronellol. In this context, argon metastable species (Ar*) likely play a key role as energy-transfer agents, promoting bond dissociation (e.g., C=C and C–H cleavage) and radical formation, which are essential steps in plasma polymerization processes[¹⁹,²¹,²²]. Overall, the OES results support the occurrence of plasma-phase activation and fragmentation mechanisms; however, due to the restricted spectral range (700–900 nm), the analysis remains qualitative and does not provide a comprehensive identification of all active species or reaction pathways.

Figure 2
Emission spectrum for the cold-plasma polymerization of citronellol in an argon atmosphere.

3.3 X-ray photoelectron spectroscopy

Figure 3 a) shows the XPS survey spectrum and atomic composition of the plasma-polymerized citronellol film (Pcit), probing approximately the upper 10 nm of the surface. The detected elements were carbon (C, 92.84% at 285.04 eV), oxygen (O, 5.56% at 531.46 eV), and a minor contribution of nitrogen (N, 1.6% at 391.5 eV). The presence of nitrogen is plausibly attributed to residual atmospheric species within the plasma reactor and/or post-deposition exposure to air. The reactor was operated at a base pressure of 0.26 Pa, a regime in which trace amounts of nitrogen are commonly detected in plasma-polymerized and plasma-treated polymeric surfaces, even in the absence of intentional nitrogen-containing precursors[²³,²⁴]. Therefore, the detected nitrogen should be regarded as an incidental surface contribution rather than as evidence of active nitrogen incorporation into the polymer backbone.

Figure 3
a) Survey spectra for Pcit (pass energy of 150 eV with a resolution of 1 eV), b) Component-fitted C1s spectra for Pcit as deposited, C1 (C-H / C-C), C2 (C-O-C / C-N / C-OH) and C3 (N-C = O, C = O).

Figure 3 b) presents the high-resolution C1s spectrum of Pcit, deconvoluted into three main components: C1 (C–C/C–H at 284.69 eV, 74.77%), C2 (C–O–C/C–N/C–OH at 285.6 eV, 16.61%), and C3 (C=O/N–C=O at 287.6 eV, 8.89%). The surface chemistry is thus dominated by hydrocarbon bonds, with a moderate fraction of oxygen-containing functional groups introduced during plasma polymerization. This composition is consistent with the measured water contact angle of 62°, indicative of a moderately hydrophilic surface. The presence of polar functionalities such as C–O and C=O groups is known to increase surface energy and water affinity, partially counterbalancing the hydrophobic character associated with the predominant hydrocarbon backbone[²³-²⁶]. While a direct causal relationship cannot be established, the relative abundance of oxidized carbon species may plausibly contribute to the observed wettability by promoting polar interactions at the solid–liquid interface. Furthermore, oxygen-containing functional groups, particularly carbonyl moieties, have been associated in the literature with antibacterial responses in plasma-modified polymeric surfaces[²³]. In this context, the XPS results suggest a surface chemistry compatible with such effects.

3.4 Attenuated total reflectance-fourier transform infrared

The infrared spectra comparison between the pure citronellol monomer and the synthesized Pcit film (Figure 4) reveals significant chemical transformations occurring during the plasma process. Given the inherent complexity of plasma-polymerized films, the resulting FTIR bands in Pcit should be interpreted as an ensemble of overlapping functional groups rather than as well-defined, discrete molecular structures[²²]. In the pure citronellol spectrum, characteristic bands include the –OH stretching at 3327 cm-1, aliphatic CH2 asymmetric and symmetric stretching at 2915 and 2851 cm-1, and signals at 1376 cm-1 and 1053 cm-1 associated with bending and stretching vibrations of the carbon skeleton and C–O bonds, respectively[²⁷]. A critical observation is the attenuation or disappearance of the features associated with the monomer's double bond (C=C) region 1670 cm-1. This loss of unsaturation provides direct evidence of the degree of monomer fragmentation and subsequent crosslinking, as the plasma energy drives the opening of double bonds to form the highly reticulated polymeric network[²²]. In the Pcit spectrum, the –OH band shifts to 3359 cm-1, suggesting its incorporation into a more complex and diverse hydrogen-bonding network within the amorphous polymer matrix[²⁸]. Furthermore, a new prominent signal at 1706 cm-1 indicates the formation of carbonyl groups (C=O). These groups arise from fragmentation and oxidation reactions during plasma synthesis, contributing to the ensemble of functionalities that may confer antibacterial properties[²³]. The emergence of new configurations in the range of 1000 to 900 cm-1, such as the signals at 1000 cm-1 and 901 cm-1, further confirms the drastic restructuring of the carbon backbone into a functionalized, crosslinked surface[²⁹].

Figure 4
ATR-FTIR spectra of Pcit and citronellol.

Based on the OES, FTIR, and XPS results, a simplified plasma polymerization pathway for citronellol is proposed, consistent with mechanisms reported for RF argon plasmas[¹⁹,²¹,²²], as illustrated in Figure 5. The argon discharge generates energetic electrons and metastable species (Ar*), which act as energy transfer agents, promoting bond scission in the precursor, particularly at the C=C bond. This process leads to the formation of carbon-centered radicals (R•), oxygenated radicals (RO•), and small hydrocarbon fragments (CxHy•). These species undergo competitive recombination and surface-driven crosslinking reactions, resulting in the formation of a highly reticulated polymeric network. The attenuation of unsaturation signals in FTIR, together with the emergence of C–O and C=O groups in XPS, supports a mechanism dominated by partial fragmentation rather than complete monomer degradation. The OES emissions in the 700–900 nm range further indicate the presence of excited argon species and reactive fragments, supporting plasma-phase activation pathways. Although intermediate species cannot be directly identified, the overall process can be described as a sequence of (i) activation via electron and Ar* interactions, (ii) fragmentation into reactive radicals, and (iii) radical-mediated surface growth, in agreement with previously reported plasma polymerization mechanisms[²¹,²²].

Figure 5
Mechanistic scheme of citronellol plasma polymerization in argon RF discharge.

3.5 Scanning electron microscopy

Figure 6 presents scanning electron microscopy (SEM) images of the Pcit obtained by cold plasma polymerization of citronellol. In micrograph (a), with a scale of 1 mm, a predominantly homogeneous surface is observed at low magnification. However, micrograph (b), with a scale of 100 µm, reveals a more complex morphology characterized by branched structures or small clusters irregularly distributed over the surface. These structures could be attributed to a combined phenomenon of localized polymerization and differences in the initial concentration of citronellol, possibly influenced by a non-uniform evaporation process under the vacuum conditions of the reactor[²²]. The differential evaporation of citronellol may have induced local gradients in the monomer density on the coverslip surface. This phenomenon could have generated regions with higher citronellol concentrations, favoring cluster formation during the plasma treatment. Additionally, the argon plasma likely played a role in redistributing the monomer and generating the observed branched structures, reflecting the interaction between plasma dynamics and the initial characteristics of the deposited monomer[³⁰]. The optical emission spectroscopy (OES) described in section 3.1 supports the hypothesis of non-uniform monomer evaporation, revealing the presence of carbon (C) and oxygen (O) ions in the plasma phase, indicating the activation of citronellol molecules and their partial fragmentation under the argon plasma conditions[³¹].

Figure 6
SEM images of Pcit, scale bar of a) 1 mm and b) 100 µm.

3.6 Roughness

The surface morphology of the plasma polymerized citronellol layer was characterized by optical profilometry using a multilayer surface 1roughness analysis, evaluating a total of nine points distributed along 21 lines. Figure 7 shows the three-dimensional height profile of a representative area of Pcit at 180% magnification. The average film thickness, determined by step-height measurements, was 0.96 ± 0.12 µm, indicating that the underlying plasma-polymerized layer is submicrometric rather than nanometric. Despite this sub-micrometric average thickness, the surface exhibited an average roughness (Ra) of 7.53 ± 2.19 µm and a maximum roughness height (Rz) of 50.57 ± 24.26 µm. These high roughness values reflect a heterogeneous surface morphology dominated by localized micrometric agglomerates rather than the intrinsic roughness of a uniform film[³]. The presence of pronounced peaks and valleys observed in the 3D height profiles is consistent with the SEM micrographs (Figure 6), which reveal micron-scale clusters and irregular growth features formed during plasma polymerization. Such agglomerates are attributed to localized variations in monomer availability and plasma-induced fragmentation recombination processes under vacuum conditions, leading to non-uniform polymer growth. Therefore, the reported roughness parameters (Ra and Rz) are predominantly governed by these micrometric surface features, while the underlying polymer layer remains sub-micrometric in thickness. This hierarchical micro–submicron topography is relevant for biomedical applications, as surface heterogeneity and roughness are known to influence protein adsorption, cell–material interactions, and antimicrobial behavior[²⁴,³¹].

Figure 7
3D height profile of the representative area of Pcit at magnifications of 180%.

3.7 Hemolysis

The evaluation of hemocompatibility is a criterion that determines the viability of biomaterials intended for medical applications, especially those with direct or indirect contact with blood. In this study, the interaction of the material Pcit with human erythrocytes was investigated through an in vitro hemolysis assay. The material was evaluated at different concentrations: 1, 2.5, and 5 mg/mL (Figure 8). The results indicated that Pcit exhibits non-hemolytic behavior, with hemolysis levels below the 5% threshold, which is considered the acceptable limit according to ASTM F 756-17[³²]. In the literature, the hemocompatibility of electrospun fibers loaded with citronellol has been evaluated, obtaining similar results, with hemolysis values below 5%[³³,³⁴], suggesting that citronellol does not induce damage to red blood cell membranes under the conditions evaluated in this assay. This finding is particularly relevant considering that citronellol is a monoterpene present in essential oils, which has been primarily studied for its antimicrobial, antioxidant, and anti-inflammatory properties, but its direct interaction with human blood cells has been scarcely documented[³³-³⁵]. The evaluation of Pcit confirms a safe profile in terms of blood compatibility.

Figure 8
In vitro hemolysis test.

3.8 Antimicrobial disk

The antimicrobial activity of Pcit against Escherichia coli and Staphylococcus aureus is presented in Table 1. Pcit exhibits measurable inhibition against both strains, indicating broad-spectrum antimicrobial behavior, although lower than the ampicillin control. This activity is plausibly associated with the intrinsic bioactivity of citronellol and the presence of oxygen-containing functional groups (C–O, C=O), which have been reported to promote interactions with bacterial membranes and oxidative stress responses in plasma-modified surfaces[²³,²⁴,³⁶]. Surface roughness (Ra ≈ 7.5 µm) may also influence bacterial adhesion by modifying local contact conditions; however, at this micrometric scale, its contribution is likely secondary compared to chemical effects[³¹]. Therefore, the antimicrobial behavior of Pcit is better interpreted as a combined effect of surface chemistry and morphology. Nevertheless, these contributions were not independently isolated, and the proposed structure–property relationship should be considered as a supported hypothesis rather than a definitive mechanism.

Table 1
Inhibition halos of Pcit.

Material	Inhibition halos (mm)
	Escherichia coli	Staphylococcus aureus
Pcit	12 ± 1	10 ± 1
Negative Control	0	0
Positive Control (Ampicillin)	25 ± 1	22 ± 1

4. Conclusions

This study demonstrates the successful plasma polymerization of citronellol (Pcit) under argon at 100 Pa, yielding a functional polymeric coating with distinct morphological, chemical, and wettability characteristics. The resulting film exhibits a heterogeneous surface composed of a sub-micrometric layer decorated with micrometric agglomerates, leading to relatively high roughness (Ra = 7.53 ± 2.19 µm; Rz = 50.57 ± 24.26 µm) and moderate hydrophilicity (WCA ≈ 62°). XPS and FTIR analyses confirmed the incorporation of oxygen-containing functional groups, while OES provided qualitative evidence of reactive species involved in plasma-phase activation and fragmentation processes. Pcit showed non-hemolytic behavior (<5%) and measurable antibacterial activity against E. coli and S. aureus. This response is more plausibly attributed to the combined effects of surface chemistry and morphology, in agreement with previous reports, although no direct causal mechanism was established. Some limitations should be acknowledged. Thickness estimation may be affected by surface heterogeneity, and biological assays were limited in statistical scope. In addition, the antimicrobial mechanism was not directly resolved and requires further investigation. Overall, these results support cold plasma polymerization as a viable strategy for converting renewable monoterpenes into functional coatings with potential applications in antibacterial and biomedical fields.

6. Acknowledgements

The authors would like to sincerely acknowledge the Secretariat of Science, Humanities, Technology, and Innovation (Secihti) for the financial support provided through the postdoctoral fellowship (grant 347182), which made this research possible. Additionally, they extend their appreciation to B. E. Reyes Vielma and M. García Zamora for their crucial technical contributions in the execution of various analytical techniques used in this study. The authors also gratefully acknowledge Dr. Zugasti Cruz for his valuable support in the performance of the hemolytic assays.

• Data Availability:
  All data supporting the findings of this study are available from the corresponding author upon request.
• How to cite:
  Martínez-Ruiz, E. O., González-López, J. A., Cuellar-Gaona, C. G., Rodríguez-Aranda, M. C., Reyes-Reyes, A., Reyes-Reyes, J. A., Ortiz-Dosal, A., Treviño-Martínez, M. E., & Neira-Velázquez, M. G. (2026). Harnessing natural monoterpenes: cold plasma polymerization of citronellol. Polímeros: Ciência e Tecnologia, 36(3), e20260027. https://doi.org/10.1590/0104-1428.20250108

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Edited by

• Associate Editor:
  Artur J. M. Valente

Data availability

All data supporting the findings of this study are available from the corresponding author upon request.

Data citations

National Institute of Standards and Technology – NIST. (2024). NIST Atomic Spectra Database (Version 5.12) (NIST Standard Reference Database, No. 78). Gaithersburg: NIST. https://doi.org/10.18434/T4W30F

Publication Dates

• Publication in this collection
  10 July 2026
• Date of issue
  2026

History

• Received
  29 Nov 2025
• Reviewed
  21 Apr 2026
• Accepted
  23 Apr 2026