Functional polymers

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Functional polymers or intelligent polymers ( English : stimuli-responsive polymers or smart polymers) are complex macromolecules whose physical and chemical properties change to a large extent but reversibly due to small changes in one or more environmental properties. This enables them to react to changes in the environment such as temperature, light or pH value.

Types of functional polymers

A distinction can be made between different types of functional polymers, for example depending on the external stimulus to which the polymer can react:

properties

Functional polymers are also characterized by specific adsorption , reactivity and transport properties and are therefore suitable as materials for sensors , actuators or membranes , for example . They can also be used for surface and interface changing, compatibilizing and other applications. Their specific properties result from the molecular and supramolecular structures of the macromolecules that make them up. Furthermore, suitable polymers can be modified using specific inorganic or organic additives in order to achieve functional polymers with these special material properties .

Functional polymers are the focus of intensive research and development activities. The classic applications of polymers are in the area of ​​construction. The application of functional polymers is in the non-structural area. Polymers with specific electrical, magnetic, optical, electrochromic, thermochromic, antibacterial, liquid-crystalline or other functional properties are of interest.

The term functional polymers is understood to mean macromolecular systems with exceptional properties as well as their combination with organic low-molecular substances or inorganic materials, nanoparticles, nanofibers or nanotubes. These are basic materials for new applications, including research into related manufacturing processes and the generation of associated equipment. The importance of functional materials based on native or synthetic polymers results from the fact that they form a material basis for technological developments and that the key technologies of this century can hardly be realized without the use of novel functional polymer materials and polymer material systems.

Despite the diverse scientific and technological activities, only a few selected applications such as organic light-emitting diodes , so-called OLEDs or polymer-based displays are available so far . The functional polymer systems are ascribed an increasing relevance for a variety of applications, for example in the areas of information and communication technology, generation, storage or conversion of energy or life sciences, which are of interest for the low-price segment and for mass markets , among other things . But applications are also being discussed in a large number of niche markets or new markets.

Products made from and with electronic functional polymers

Functional textiles and composite textile structures

  • Functional layers on textile surfaces; Active substance-carrying textile fibers
  • electrically conductive and piezoelectric fibers and textiles
  • Intelligent adaptive textiles and transfer systems; "Smart clothings"
  • Biocompatible textile constructs; "Tissue engineering materials"
  • Chromatography, apheresis, adsorber fibers; "Drug delivery systems"

Potentials and areas of application

The most important applications for functional polymers can currently be found in the health sector. This includes, for example, the targeted release of drugs in the body through external stimuli.

Functional polymer systems also offer potential, primarily resulting from the possible combinations of individual components in microsystems, such as sensors and actuators with fluidics and logic in the case of sensor array chips, which consist of microfluidic structures, actuators and suitable sensors as well as evaluation and communication electronics ("lab on a chip "). Functional polymers also allow structuring and production technologies such as printing. Compared to the application of conventional semiconductor materials, the use of functional polymer materials has a number of advantages, especially in the ability to combine and integrate different functionalities, in the adaptability to external influencing factors and environmental conditions, in the free design, in the applicability of technologies low manufacturing costs and suitability for mass production can be seen.

Vehicle and mechanical engineering is strongly characterized by the integration of additional sensors, actuators, electronics, control technology, mechatronics and adaptronics as well as the use of special materials with specific polymer-based functionalities, including the further development of design principles and the evaluation of the operational safety of the resulting products.

Smart hydrogels

The sensitivity of smart hydrogels to external influences is usually caused by ions anchored in the network, which, through a mixture of chemical, electrical and mechanical interaction effects, cause differences in ion concentrations inside and outside the gel. As a result, the water is forced into or out of the gel by osmosis and a changing expansion of the gel is triggered. In return, mechanical deformation can generate an electrical potential difference between two points of the gel with constant boundary conditions, whereby the deformation can be measured and quantified. Smart hydrogels therefore have integrated actuator-sensor functions, ie they combine sensors and actuators in a single element. This is used, for example, in chemostats .

Smart hydrogels are expected to provide considerable impetus for chemical sensors , microsystem technology and microfluidics , control technology and medical technology . Sometimes smart hydrogels are also referred to as chemomechanical actuators .

See also

literature

  • A. Herrmann: Makromolekulare Chemie 2008 (trend report) . Nachrichten aus der Chemie 57 (3) 2009, 297-304.
  • A. Schmidt, H. Frauenrath: Makromolekulare Chemie 2007 (trend report) . News from chemistry 56 (3) 2008, 315-324.
  • M. Grüne, S. Reschke, J. Kohlhoff: Material trends: electronic functional polymers . Materials in Manufacturing (2008), 1.3ff.
  • H. Schlaad, HG Börner: Makromolekulare Chemie 2006 (trend report) . News from chemistry 55 (3) 2007, 306-312.
  • R. Pfaendner: Functional polymers through controlled reactions and their applications . KGK (2006) 11, 582-589.
  • D. Hertel, CD Müller, K. Meerholz: Image generation - organic light-emitting diodes . Chem. Our time, 2005, 39, 336-347.
  • A. Göthlich, S. Koltzenburg, G. Schornick: Versatile - Functional Polymers in Everyday Life . Chem. Our time, 2005, 39, 262-273.
  • J. Bohrisch, M. Hahn: Novel switchable hydrogels . Fraunhofer IAP Annual Report 2004/2005, 64–65.
  • E. Görnitz, B.-R. Paulke: From polymer colloids to photonic materials . Fraunhofer IAP Annual Report 2003, 70–71.
  • E. Winkler, H. Pielartzik, A. Schneller: Functional Polymers . Angew. Macromol. Chemie 244 (1997), 161-181.
  • H.-K. Roth, M. Schrödner: Application fields of organic functional polymers , polymer actuators and polymer transistors . Mat.-scientific u. Materials tech. 34 (2003) 3: 254-261.

Web links

Individual evidence

  1. ↑ a b c María Rosa Aguilar & Julio San Román: Smart Polymers and their Applications . Elsevier Science, 2014, ISBN 978-0-85709-695-1 , pp. 1-298 .
  2. ^ Ballhauser and Wallmersperger: Coupled chemo-electro-mechanical finite element simulation of hydrogels: I. Chemical stimulation