Smart Mesoporous Silica Nanocapsules as Environmentally Friendly Anticorrosive Pigments

C Zea,D De La Fuente,R Barranco-García,B Chico,M Morcillo,I Díaz

doi:10.1155/2015/426397

C Zea, D De La Fuente + Show 4 more

Open Access

https://doi.org/10.1155/2015/426397

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Abstract

Nowadays there is a special interest to study and develop new smart anticorrosive pigments in order to increase the protection life time of organic coatings and, simultaneously, to find alternatives to conventional toxic and carcinogenic hexavalent chromium compounds. In this respect, the great development of nanotechnologies in recent years has opened up a range of possibilities in the field of anticorrosive paints through the integration of encapsulated nanoscale containers loaded with active components into coatings. By means of a suitable design of the capsule, the release of the encapsulated corrosion inhibitor can be triggered by different external or internal factors (pH change, mechanical damage, etc.) thus preventing spontaneous leakage of the active component and achieving more efficient and economical use of the inhibitor, which is only released upon demand in the affected area. In the present work, the improved anticorrosive behaviour achieved by encapsulated mesoporous silica nanocontainers filled with an environmentally friendly corrosion inhibitor has been evaluated. It has been proven that a change in the pH allows the rupture of the capsules, the release of the inhibitor, and the successful protection of the carbon steel substrate.

Highlights

The application of protective organic coatings is one of the most widespread approaches used nowadays for corrosion protection of different metallic materials
The great development of nanotechnologies in recent years has opened up a range of possibilities in the field of anticorrosive paints through the integration of encapsulated nanoscale containers loaded with active components into coatings
By means of a suitable design of the capsule, the release of the encapsulated corrosion inhibitor can be triggered by different external or internal factors preventing spontaneous leakage of the active component and achieving more efficient and economical use of the inhibitor, which is only released upon demand in the affected area

Summary

Introduction

The application of protective organic coatings is one of the most widespread approaches used nowadays for corrosion protection of different metallic materials. The toxicity of these pigments to human health, given their carcinogenic effects [3], and to the environment [4, 5] is giving rise to severe restrictions on their use [6, 7] All of this has spawned an exhaustive search for environmentally friendly alternatives to replace this type of anticorrosive pigments and has become the great challenge of the last years for all the sectors involved in anticorrosive protection by organic coatings. Nanocontainers are uniformly distributed in the passive matrix keeping active material in a “trapped” state, avoiding the undesirable interaction between the active component and the passive matrix, leading to spontaneous leakage Release from such a shell-like capsule is typically realized by its rupture and a prompt liberation of the carried substance. The loading and releasing capacity at different conditions has been determined and the inhibition capacity has been obtained from polarization curves of carbon steel exposed to solutions of a different aggressiveness in presence of loaded nanoreservoirs

Experimental Procedure

Results and Discussion

Conclusions