Zn and Al vapour-phase metalation of polyamide-6 via ALD : structural, functional, and biomedical insights

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Moreno, Mabel and Devis, Sindy and Velasquez, Luis and Arredondo, Miryam and Mariotti, Davide and McGlynn, Ruairi and Sanchéz-Ruderisch, Hugo and Quijada, Raúl and González, Guillermo and Olguin, Yusser and Solar, Paula and Zacarias, Angelica and Gross, Eberhard K.U. (2025) Zn and Al vapour-phase metalation of polyamide-6 via ALD : structural, functional, and biomedical insights. Journal of Materials Science, 60 (44). 22203–22233. ISSN 0022-2461 (https://doi.org/10.1007/s10853-025-11168-y)

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Abstract

This study reports the effect of diethylzinc (DEZ) and trimethylaluminium (TMA) functionalization on polyamide-6 (PA6) films using the vapour-phase metalation (VPM) process within an atomic layer deposition (ALD) chamber. The resulting zinc- and aluminium-functionalized films are referred to henceforth as PA6-Zn and PA6-Al, respectively. Biocompatibility was preliminarily assessed via C2C12 cytotoxicity testing. Reaction mechanisms were examined using density functional theory, electrostatic potential maps, Mulliken charge distribution, and X-ray photoelectron spectroscopy, revealing interactions between metal precursors and PA6 amide groups. DFT confirmed α-PA6 as the dominant structure and identified reactive sites influencing functionalization pathways. Structural and morphological changes were analysed via environmental scanning electron microscopy and X-ray diffraction. ESEM showed Zn-functionalized PA6 forming strand-like structures, while Al-functionalized PA6 developed pore-like cavities. XRD indicated increased crystallinity upon metalation, with the α/γ crystallite size ratio following the trend: PA6-Al > PA6-Zn > PA6. Spectroscopic analysis using infrared and Raman microscopy, along with UV–visible spectroscopy, highlighted modifications in chemical bonding and polymorphism, aligning with DFT predictions. Al functionalization had a stronger influence on PA6’s spectroscopic and some mechanical properties, whereas Zn functionalization notably enhanced failure strain. Barrier and mechanical properties were evaluated, showing that Zn-functionalized PA6 exhibited superior oxygen permeability, while both metal-modified films improved water vapour transmission rates compared to bare PA6. Cytotoxicity testing revealed enhanced C2C12 cell proliferation in the order PA6-Al > PA6-Zn > PA6, suggesting VPM-modified PA6 as a promising material for biomedical applications.

ORCID iDs

Moreno, Mabel, Devis, Sindy, Velasquez, Luis, Arredondo, Miryam, Mariotti, Davide ORCID logoORCID: https://orcid.org/0000-0003-1504-4383, McGlynn, Ruairi, Sanchéz-Ruderisch, Hugo, Quijada, Raúl, González, Guillermo, Olguin, Yusser, Solar, Paula, Zacarias, Angelica and Gross, Eberhard K.U.;
CORE (COnnecting REpositories)