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Smart anticorrosion coatings based on nanocontainers loaded with novel, eco-friendly cationic gemini surfactants as efficient corrosion inhibitors for carbon steel in seawater.

Periodic Reporting for period 1 - EcoGemCoat (Smart anticorrosion coatings based on nanocontainers loaded with novel, eco-friendly cationic gemini surfactants as efficient corrosion inhibitors for carbon steel in seawater.)

Reporting period: 2018-09-03 to 2020-09-02

Corrosion poses a serious threat to the extended service life of infrastructure, utilities, transportation and products which are used in different industries (marine, offshore, petrochemical, automotive, food, among others) but also in daily life as we live in metal-based society. Corrosion leads to financial losses (more than 1 billion US$), and relates to safety and environmental hazards. Searching for more efficient protection of metal-based structural components to increase their service life and reduce maintenance costs will help saving money and protect people and the environment.

Corrosion inhibitors are chemical compounds which can prevent corrosion of metals. Entrapping them in nanocontainers and afterwards incorporating the loaded nanomaterials into protective functional coatings (smart coatings) can lead to a more effective, long-lasting corrosion protection.

In this context, EcoGemCoat project aimed at the development of smart anticorrosion coatings based on nanocontainers loaded with corrosion inhibitors for carbon steel with a potential application in marine and offshore industry.
The overall objectives of the project were:
• Preparation of inhibitors;
• Testing of inhibitors;
• Preparation of smart coatings;
• Corrosion, mechanical and environmental test of coatings;
• Gaining new skills and developing researcher’s career;
• Dissemination and communication of the project results.
The work performed within EcoGemCoat consisted of four work packages (WP). In WP 1 corrosion inhibitors (ie. cationic gemini surfactants) were prepared. In WP 2 the inhibitors were tested (corrosion and ecotoxicity tests). Ecotoxicity test were carried out in collaboration with Department of Biology and Centre for Environmental and Marine Studies CESAM from the University of Aveiro. The most effective corrosion inhibitor (QSB2-12) was chosen for WP 3 in which smart anticorrosion coatings were prepared. In order to achieve that, first the corrosion inhibitor was immobilized into nanocontainers. Then, the resulting anticorrosive were prepared and characterised (WP4). The ability for the coatings to prevent corrosion of underlying steel substrates in neutral saline environment was studied by electrochemical corrosion tests. Additional mechanical testing based on tensile test with coupled electrochemical corrosion test was performed during the secondment at the University of Manchester. Ecotoxicity of the coatings was evaluated in CESAM.

The main results of EcoGemCoat are as follows:
• Ecotoxicity tests of the synthesised gemini surfactants towards marine microorganisms were obtained (WP 2). The tests showed that cationic gemini surfactants are less toxic than the monomeric surfactant CTAB and that they can be a more environmentally friendly substitute in various applications.
• The synthesised corrosion inhibitors (gemini surfactants) were tested in order to prevent corrosion of carbon steel in sodium chloride solution (WP 2). The tests showed that they are not the most effective, but their inhibition efficiency (IE) is 20% higher than IE for the monomeric surfactant DTAC.
• Novel gemini surfactant-based silica nanocapsules (Si_QSB) with lower toxicity were successfully synthesised and characterised (WP 3).
• Replacement of CTAB, which is commonly used as a template surfactant for silica nanocapsules synthesis, with less toxic gemini surfactant QSB2-12 is consistent with Safe-by-Design approaches for the synthesis of functional nanomaterials (WP 3).
• Ecotoxicity tests of coatings with free corrosion inhibitor (QSB2-12) and novel silica nanocapsules (Si_QSB) incorporated were carried out (WP 4).
• Development of the Fellow’s career which included gaining new skills, participation in conferences and a winter school, teaching activities at the University of Aveiro, supervision activities, writing scientific publications and grant proposals, project management and communications activities, was achieved.

The project results were presented in 3 international conferences (one presentation was awarded with Best oral presentation prize), published in scientific journals and conference proceedings, as well as presented to research groups (University of Aveiro and University of Manchester) during seminars. Communication to general public included participation and organization of workshops, webinars, exhibitions and an open lab day. News about EcoGemCoat progress were also spread on social media (Facebook and Twitter).
Results of EcoGemCoat contributed to the knowledge on the properties of cationic gemini surfactants, namely corrosion inhibition efficiency for carbon steel in sodium chloride solutions and ecotoxicity data towards marine species. Additionally, the work performed within the project opened a safe-by-designed approach to the nanomaterials production. The developed silica nanocapsules with reduced marine ecotoxicity have a potential to be lunched to the market and it can strengthen competitiveness and growth of companies which produce nanoadditives for marine applications.

All the communication activities undertaken in the frame of the project supported an investment in education and spreading information about corrosion and its detrimental impact. Additionally, the workshop organised for Polish children living in Portugal supports the respect for Polish language and promotes interculturality.