SMART POLYMERS, The "Chameleon" principle

These very to-date technological advances in polymer science were taken from the American Coatings Show in Carolina, see www.american-coatings-show.com


By: Sergiy Minko, Clarkson University

Stimuli-responsive macromolecular nanostructures are capable of conformational and chemical changes upon “receiving an external signal” such as a change in temperature, chemical composition, applied mechanical force, irradiation with light, or exposure to an electrical or magnetic field. The changes at the molecular level are accompanied by variations in physical properties at a macroscale. These principles were explored in the development of reconstructable surfaces. Reconstructable surfaces change their wettability, permeability, and adhesive, adsorptive, mechanical, and optical properties. Various applications extend to materials with rapidly switchable adhesion (from sticky to nonsticky) and wetting (from wettable to non-wettable), with switchable appearance and transparency, and coatings capable of rapid release of chemicals, as well as self-healing coatings.

Reconstructable polymer surfaces form a toolbox for the rapidly developing field of smart coatings. The structure of the coatings can be programmed in the formulation. After deposition, external stimuli affect the spatial arrangement of the ingredients and direct the assembly of the coating with programmed properties.


By: Brij Mohal, Evonik


Smart coatings are often referred to as structured coatings which provide additional benefits by giving an appropriate response to outside conditions. There has been much talk about self-healing or super hydrophobic and hydrophilic coatings, to name a few. More examples will be given in this session, comprising dirt resistant coatings, as well as stimuli responsive polymeric polymers acting on demand. Other interesting developments are anti-fog coatings and the use of natural materials in order to achieve functionality.

By: Jamil Baghdachi, Eastern Michigan University

Introduction: Surface coatings function to protect or improve the appearance of a substrate or both. No matter how carefully the coatings are designed, manufactured and applied, all will eventually fail through some type of force in excess of the tolerance level of the coating or its ingredients. Failure of a coating system occurs by any number of failure modes and can often be attributed to a number of root causes including coating degradation, mechanical damage, or polymer fatigue upon service and exposure to elements of weather.

The concept of self healing materials has drawn significant attention of researchers all over the world.1-10 Self-healing and self-repair concept, using both organic and inorganic materials have been applied to composites, plastics, concrete, adhesives, artificial skin, and most recently to functional coatings.

In an effort to mimic self-healing functions in living systems, we have the developed polymeric coating systems that are stimuli responsive. The most attractive feature of this system is that the factors that damage the coating the most, such as humidity, exposure to high temperatures etc., are the same factors that initiate self-healing phenomenon (Figure 1). This property is unique since the extent of the healing is proportional to the magnitude of the damage, i.e., release on demand.