German research shows smart polymer films could be used to diagnose diseases

Researchers at the Technical University of Darmstadt (TUD) in Germany are investigating the possibility of selectively controlling the properties of the underlying substrate material based on ultra-thin "smart" plastic films. For example, paper could be made to automatically release ink when needed, chemical reactions could be started and interrupted under catalytic control, or drug systems could be tailored to specific parts of the human body.

The TUD research team is studying a variety of polymer films (in some cases only one molecule thick), with a variety of chemical compositions and physical structures. Some polymer films have rigid rod-like structures, others have flexible "tails" on the rods that connect them to form a film; and still others behave in a way that is similar to a ball of yarn or overcooked noodles. The researchers are starting by trying to understand the basic molecular mechanisms that will allow polymer films to become fast-acting and efficient electronic microcircuits.

Dr. Markus Biesalski, project coordinator for TUD's Soft Control, says that once the underlying mechanism is understood, the material could be used in a wide range of applications. He continues: "One practical application of such switchable films is the reversible wetting of surfaces, which is ideal for ink applications. A 'smart' plastic film added to the material to be printed would allow the ink to adhere to it with maximum force during initial use, but would then be easily removed during recycling by switching to a repelling effect."

"Another area of ​​application is the catalytic control of chemical reactions. Light of a certain wavelength can change the polymer structure of the film, thereby inhibiting the activity of the catalyst on the underlying substrate. Switching to a different wavelength can restart the catalysis and thus promote the chemical reaction. The same effect can be used to control the on/off switching of sensors.

"In the longer term, polymer films could be used to make new types of biosensors, for example to detect environmental pollutants or diagnose disease."