Scalable enzymatic polymerization of thin-film coatings on metal and synthetic polymer surfaces

Nenninger, Chiara; Schwaneberg, Ulrich; Herres-Pawlis, Sonja

doi:45191

Scalable enzymatic polymerization of thin-film coatings on metal and synthetic polymer surfaces

Nenninger, Chiara^RWTH*

2026

Verantwortlichkeitsangabevorgelegt von Chiara Nenninger Master of Science Molekulare Biotechnologie

ImpressumAachen 2026

Umfangv, 140 Seiten : Illustrationen

Dissertation, RWTH Aachen University, 2026

Genehmigende Fakultät
Fak01

Hauptberichter/Gutachter
Schwaneberg, Ulrich (Thesis advisor)^RWTH* ; Herres-Pawlis, Sonja (Thesis advisor)^RWTH*

Tag der mündlichen Prüfung/Habilitation
2026-03-20

Online
URL: https://digitale-objekte.hbz-nrw.de/storage2/2026/06/14/file_15/10145795.pdf

Einrichtungen

Inhaltliche Beschreibung (Schlagwörter)
biocatalysis (frei) ; corrosion protection (frei) ; enzymatic polymerization (frei) ; enzyme immobilization (frei) ; protein-based coatings (frei) ; thin-film coatings (frei)

Thematische Einordnung (Klassifikation)
DDC: 570

Kurzfassung
From the shiny finishes of cars to the biocompatible coatings on medical implants, thin film coatings play a critical role in modern life. Thin-film coatings that are corrosion resistant, conductive, anti-microbial, or hydrophobic transform inexpensive materials, like synthetic polymers and metal alloys, into high-performance materials. Chemical and physical methods are broadly used to generate thin-film coatings. Achieving uniform surface functionalization, broad material compatibility, control over film thickness, and scalability that is also sustainable presents a complex challenge. Enzymatic polymerization could be a solution to these challenges, using proteins as renewable resources. Enzymatic polymerization with laccases is a promising alternative since oxygen is used to initiate the polymerization reaction at ambient temperature, atmospheric pressure in an aqueous solution. A fusion protein combining a laccase, the copper efflux oxidase (CueO), and the adhesion-promoting peptide (AP) Macaque Histatin (MacHis) was employed to generate thin-film coatings. The AP MacHis immobilizes CueO in an oriented manner on the material surface, preserving its catalytic activity for the polymerization reaction. Polypyrrole (PPy) was selected as polymer due to its conductive, biocompatible, and corrosion-resistant properties. Corrosion resistant coatings are needed to extend the longevity and durability of metals and metal alloys from environmental influences, saving billions of US$ annually in corrosion related costs worldwide. To demonstrate the method’s broad applicability, CueO-MacHis was immobilized on two metal alloys and six synthetic polymers, generating anti-corrosive and conductive thin-film coatings. The polymerization reaction stops “automatically” at a height of 30 nm, when immobilized CueO-MacHis becomes encapsulated by the PPy-coating. The method’s scalability was demonstrated by functionalizing a stainless steel plate measuring 30 × 100 × 0.02 cm with CueO-MacHis via spraying, followed by PPy-coating formation through immersion in the reaction mix. The durability of the protein-based coatings on metal alloys was characterized according to an alternating corrosion test (DIN EN 60068-2-52 test method 3), an acid resistance test, a pencil hardness test (DIN EN ISO 15184:2020-05), and a pull-off adhesion test (DIN EN ISO 4624:2023-09). The conductivity of the PPy-coatings on non-conductive synthetic polymer surfaces was in the range of 109 to 8250 kΩ sq-1. This work presents a resource- and energy-efficient enzymatic coating method that serves as a versatile platform for the development of coatings on diverse material surfaces.

External link:

Table of contents