Functional Polymers

Polymers are a remarkably versatile materials class that pervades our life in a variety of applications. JGU and MPI-P are internationally recognized leading centers in polymer research, encompassing polymer theory, synthesis and structure formation. Research at MAINZ comprises the synthesis of polymer materials and the investigation and tailoring of their properties. This research provides a toolbox for designing materials from the molecular level to the micrometer scale with a desired Function-through-Structure. Exciting new research fields are being developed based on new materials, such as nanographene with tailored electronic and magnetic properties linking to the research area of Correlated Matter. The synthesis of functional polymeric particles and polymers for surface functionalization as well as bio-compatible and bio-degradable polymers is a research focus providing links to the research areas Hybrid Structures and Bio-Related Materials.

The research area Functional Polymers comprises the synthesis of polymer materials and the investigation and tuning of their properties. On the one hand, polymers with specific functions are exciting due to the underlying physics and chemistry principles that result in outstanding tunability of the resulting properties. On the other hand, functional polymers govern our lives in a variety of applications ranging from coatings with specific surface functionality to polymer foams that are indispensable for modern construction and building applications.

For almost three decades, JGU and MPI-P in Mainz have been internationally recognized leading centers of polymer research. JGU and the adjacent MPI-P share a tradition of collaborative research that encompasses several CRC initiatives (currently the CRC625), national and international research and training schools as well as European projects. Recent evaluations have repeatedly confirmed the high reputation of polymer theory, synthesis and structure formationat MPI-P and at the Faculties of Chemistry and Physics at JGU.

At MAINZ research in this area can be divided into a number of subareas, covering the entire structural hierarchy of polymer-based materials from the molecular level to the micrometer scale.This starts with the development of new monomer and comonomer structures to extend the toolkit of advanced polymer synthesis in general and continues with studying the interactions of polymers at the next hierarchical level. The respective teams design new monomer building units with broadly varied chemistry. These units permit to obtain unprecedented copolymers and particular functionalities of the resulting polymer structures. Examples include new types of biocompatible multifunctional polyethers, which have been designed and are highly suitable for bioconjugation (Frey). Alternatively,new biocompatible block-copolymers or specifically α, ω− functionalized polymers became available by controlled-radical polymerization (Zentel). These polymers also play a role in the area of Bio-Related Materials. All current cutting-edge techniques for polymer synthesis are used by the participating research groups, enabling MAINZ to cover the entire spectrum of techniques from e.g., advanced anionic and “living” radical polymerization techniques to surface-controlled polymerization strategies, which is important in view of a broad education of the MAINZ graduates.These efforts are complemented by research into novel methods and techniques for functional polymer synthesis. One example is the use of microreactors (Frey, Zentel) as an innovative tool for broad structural variation of copolymers in cooperation with the Institut für Mikrotechnik Mainz (IMM).

MAINZ efforts in functional polymer synthesis also encompass a wide range of emulsion polymerization strategies to generate functional polymer micro- and nanoparticles (Landfester,Müllen, Zentel). This allows to tune size on different length scales (5 nm – several μm) and surface functionality, and to synthesize polymer particles with liquid crystalline substructure that are useful for sensors or actuators. Together with the biocompatible polymers mentioned above, they can also be used for medical and pharmaceutical applications; that is to target specific tissues or to transport a defined drug payload. Two-dimensional polymers are prepared by placing the monomer structures on surfaces and subsequent polymerization in the pre-organized state (Müllen, Kühnle). The objective of Function-through-Structure is realized by self-organization of specifically functionalized polymers, such as polymer brushes, block copolymers and polymer-functionalized nanoparticles. Non-covalent interaction forces are exploited to obtain aggregate structures and – on the next hierarchical level – tailor-made materials whose properties are controlled on the less complex molecular level.

An example for the Rational Design of materials at MAINZ is the field of optoelectronics (e.g., displays and photovoltaic solar cells). Scientifically, we concentrate on the aspect of self-organized structures to realize desired optoelectronic functions (Andrienko, Kremer, Müllen). A number of self-organizing materials, including liquid crystalline and block copolymers are used to obtain the desired functions. This work has strong links to the research area Hybrid Structures and is integrated into the IRTG1404. In this area, dimensionality plays a keyrole, since interfacial 2D phenomena underlie the most relevant 3D device characteristics. Another example of activities including reduced dimensions are polymers at surfaces, which influence or even dominate the function of materials in many applications. These polymers at surfaces stabilize polymer dispersions and govern their rheological properties. Wetting properties and adhesion are determined by the surfaces/interfaces. In addition to well-known functions as coloring or corrosion protection, polymers at surfaces can have highly specialized functions. Examples include plasmacoated surfaces for biomedical applications (Landfester) and, thus, provide a link towards Bio-Related Materials.

New research activities

The extension of the advanced polymer synthesis toolkit described above leads to the design of new functional polymers relevant for the area of Model Systems and Correlated Matter such as charge transfer salts with controlled correlations. These polymers open up the possibility of obtaining organic materials with properties like superconductivity and magnetism. Furthermore, we use functional polymers that are relevant for bio-medical applications. We study bio-degradable and bio-compatible homo- and block copolymer structures such as multifunctional poly(ethyleneglycol)s (mf-PEG) or block copolymers based on hydroxypropyl methacrylate. These polymers as well as polymer aggregates and nanoparticles coated with polymers are used in the context of controlled release (Frey, Landfester, Schmidt, Zentel). This subarea contributes to the field of healthcare. The complex functions of biological systems necessitate a Rational Design of the respective materials. The activities in this direction resulted in a number of joint projects together with research teams of the University Medical Center of JGU, e.g., the recently submitted CRC proposal on “Nanodimensional polymeric therapeutics for tumor therapy”.

Teaching, learning and training opportunities

Synthesis and Characterization comprise all modern synthesis methods for polymers and represent a unique teaching and training opportunity. Close collaboration between groups working on Synthesis and Characterization as well as Theory and Simulations within MAINZ allows us to focus our training on Rational Design of new functional polymers monomer structures to the final material, spanning a wide range of complexity and dimensionality. The opportunities in this area are enhanced by manifold ties of the participating PIs to leading companies (e.g., BASF) and the IMM. Training at the bench, including Method Development, bridges to neighboring research areas, as many characterization methods are employed in different research areas. It is obvious that these topics are also highly relevant in view of the interdisciplinary training of PhD students with expertise in biomedical materials. Therefore, possible joint training activities with the recently established graduate school TRANSMED are envisioned.

Connection to other research areas of MAINZ

Research performed within the field of Functional Polymers provides several links to the other research areas of MAINZ. Tailor-made, functional polymers are used in Correlated Matter as well as in Hybrid Structures, where block copolymers with specific functionalities are often used. Mastering the synthesis and consequently the functionality of polymers constitutes a prerequisite for successful fabrication of organic-inorganic hybrid nanostructures. Since the structural synthesis of graphenebased nanostructures allows to tailor electronic and magnetic properties, these structures constitute a prototype materials class linking to the research area Correlated Matter. Moreover, a very strong collaboration exists, linking this research area to the field of bio-mimetic materials and in particular bio-medically relevant polymers, which are used in the research area Bio-Related Materials. Many theoretical concepts, including those from the research area of Model Systems and Correlated Matter, can be advantageously applied to understand polymers with non-trivial electronic correlations and molecules with tuned dimensionality.