Chromogenic Polymers

Appealing Materials − Chromogenic Polymers

Chromogenic materials change color and transparency reacting to temperature, voltage, pressure or light. They can also be specifically controlled by external stimuli.

In the research department »Chromogenic Polymers« at the Fraunhofer Institute for Applied Polymer Research IAP enabling plastics to change color is one of our main subjects. Our focus is on thermochromic polymers. We develop hydrogels, thermoplastics (foils), thermosets and additives which change their color and/or transparency at a change of temperature. The application potential of these materials lies among others in solar technique, engineering, automotive, and information technique.

We cover every step of the value chain:

concept > dye development > chromogenic composite > protection technology > extrusion / polymer melt > chromogenic product


Variable − Overview of Chromogenic Polymers

In recent years, interest in functional polymers that change their visual appearance depending on an external stimulus has grown steadily. Accordingly, these chromogenic polymers are classified as thermochromic (stimulus: temperature), photochromic (stimulus: light), electrochromic (stimulus: electric voltage), mechanochromic (stimulus: pressure), ionochromic (stimulus: ion concentration), and biochromic (stimulus: biochemical reaction). Due to their functional properties, which open up new innovative fields of application, it is to be expected that the demand for chromogenic polymers will increase in the future.



Material that changes color in reaction to a change of temperature is equipped with thermochromic properties.



The temperature-dependent change in the transparency of a material that changes between a clear and a strongly scattering state is called thermotropy.



If color change is controlled by voltage the effect is called electrochromic.



The color change caused by a mechanical pressure is called mechanochromic effect.


The color change of a material caused by exposure with light is called photochromism.

Plastics Processing

In our technical center, we can process the materials we developed directly into thermoplastic materials.

We also process your polymers!

Material Characteristics

Our extensively equipped optics laboratory enables a precise characterization of the materials we develop.

We are happy to help you with your requests about structure elucidation.


Using various 3D printers and scanners, we can manufacture plastic prototypes according to your specifications. Additionally, we have a CNC milling machine and various other devices for the abrasive processing of plastics.

Our Services

Consulting on the following topics

  • active or passive switching materials for the regulation of energy and light input
  • color-changing effects
  • Individual research solutions for color changing materials
  • active and passive switching
  • reversible or irreversible
  • various matrices: thermoplastics, elastomers, duromers, casting resins, hydrogels, paints and other material classes

Plastics Processing

  • masterbatches
  • press plates
  • mono- and multilayer films
Prototype manufacturing through 3D printing and scanning processes, as well as plastic machining with CNC.

Micro- and nanoencapsulation of color change materials and additives


Spray drying of suspensions, emulsions or solutions


Material testing based on

  • DIN EN 60068-2-30; DIN EN ISO 12543-4: Climatic testing of laminated glass
  • DIN EN 410: Determination of photometric characteristics of glazing

Characterization of surface topologies with 3D digital microscopy

  • high depth of field
  • suitable for highly reflective surfaces

Investigation of material properties

  • interfacial properties
  • thermo-optical behavior

Literature – Highlights

D. Lötzsch, V. Eberhardt, C. Rabe

Chromogenic Materials

Ullmann's Encyclopedia of Industrial Chemistry (2016) | DOI: 10.1002/14356007.t07_t01

A. Seeboth, D. Lötzsch , R. Ruhmann, O. Muehling

Thermochromic Polymers – Function by Design

Chemical Reviews 114 (5), p. 3037–3068 (2014) | DOI: 10.1021/cr400462e

A. Seeboth, D. Lötzsch, R. Ruhmann

First example of a non-toxic thermochromic polymer material – based on a novel mechanism

Journal of Materials Chemistry C 1(16), p. 2811-2816 (2013) | DOI: 10.1039/C3TC30094C