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RESEARCH PROFILE

Associate Professor Dr. Daniel Crespy

Materials Science and Engineering
Molecular Science and Engineering
Tel. 006633014153
Email daniel.crespy@vistec.ac.th
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Anticorrosion and Self-Healing

 

Research Overview

The efficient use of energy and resources is a major topic for industrial and academic chemistry. We propose approaches that can allow for prolonging the life cycle of materials. Our group, which is expert in microencapsulation technologies, design new nanocapsules for creating materials that can heal themselves upon mechanical or chemical damages.

Keywords: Anticorrosion; self-healing; self-repairing; smart materials; stimuli-responsive materials

The age of self-healing materials

Humanity has realized that the available resources and energy needs to be consumed more efficiently to live in a sustainable society. A topic of research that tackles this issue is related to the synthesis of so-called self-healing materials, i.e. materials able to heal at least partially damages that they may suffer. The concept of self-healing materials is a paradigm shift in materials science and leads the academic and industrial community to new exciting advances and benefits. The contribution of our group of chemists in VISTEC is the creation of unique new self-healing materials based on smart nanocapsules.

Self-healing for prolonging lifetime of materials

Our main interest is to create materials that can autonomously self-repair, i.e. that can heal without external human intervention and at room temperature. Therefore, we developed new methods for the encapsulation of reactive agents such as monomers and catalysts in inorganic [1] or polymer nanocapsules [2-4] that can be used in a self-healing reaction and for which the release can be triggered by mechanical damage or environmental stimuli.

Moreover, our approach is very versatile and a very wide range of materials can be used as core and shell for building the smart nanocapsules such as organic or inorganic shell and polymer or liquid cores. The nanocapsules surfaces were functionalized with various chemical groups [1-3] to enhance their compatibility with the host matrix. Moreover, stimulus-responsive materials, i.e. materials responsive to changes of pH value, redox conditions, or temperature, were synthesized and used as nanocontainers to allow for selective release of the healing agents. Such nanocontainers can be further embedded in coatings to yield materials with self-healing abilities (see Figure 1).


Figure 1. Scanning electron microscopy cross-section images of smart nanocontainers embedded in an acrylate coating at different magnitudes (a-c). From reference [5].

Materials for anticorrosion

Corrosion is a major economical plague and financial plague. It was calculated that corrosion was responsible for a loss of ~107 Billions Bahts in Thailand in 2011. Therefore, it is suitable to develop new materials that can hinder or stop corrosion [5-7]. We have developed the first real corrosion-responsive self-healing material [6-7], a material that activates its self-repairing properties only when corrosion occurs (Figure 2). This revolutionary material was proved to stop efficiently the corrosion of zinc. We now create materials that can achieve similar properties, but for other metals and based on Thai renewable resources.


Figure 2. Scheme displaying the self-healing reaction at the delamination front upon onset of corrosion. From reference 7.

 

Selected Publications

[1] Fickert, J.; Rupper, P.; Graf, R.; Landfester, K.; Crespy, D. J. Mater. Chem. 2012, 22, 2286
[2] Fickert, J.; Makowski, M.; Kappl, M.; Landfester, K.; Crespy, D. Macromolecules 2012, 45, 6324
[3] Fickert, J.; Wohnhaas, C.; Turshatov, A.; Landfester, K.; Crespy, D. Macromolecules 2013, 46, 573
[4] Zhao, Y.; Fickert, J.; Landfester, K.; Crespy, D. Small 2012, 8, 2954 
  [5] Lv, L.-P.; Zhao, Y.; Vilbrandt, N.; Gallei, M.; Vimalanandan, A.; Rohwerder, M.; Landfester, K.; Crespy, D. J. Amer. Chem. Soc. 2013, 135, 14198
[6] Vimalanandan, A.; Lv, L.P.; Tran, T.H.; Landfester, K.; Crespy, D.; Rohwerder, M. Adv. Mater. 2013, 25, 6980
[7] Tran, T.H.; Vimalanandan, A.; Genchev, G.; Fickert, J.; Landfester, K.; Crespy, D.; Rohwerder, M. Adv. Mater. 2015, 27, 3825