Research group Prof. Dr. Jörg August Becker

The focus of the Becker research group - Chair of Physical Chemistry - is on the experimental and theoretical investigation of structures and dynamics in molecules and complex interfaces. The research work is carried out in cooperation with material scientists from the field of mechanical engineering and partners from industry.

RESEARCH EXPERTISE: REACTION AND STRUCTURE FORMATION IN SOLID STATE INTERFACES

In the group, reactions and structure formation in solid-state interfaces and the dynamics of these processes are investigated. We pursue both an experimental and a theoretical approach. Specially developed experimental equipment and methods adapted to the demanding reactive conditions are used. Theoretically, we develop models that describe the complex interfaces with their dynamic reaction layers in order to gain insight into the processes at the molecular level. The goal is a better understanding of dynamics, reactions and transport phenomena in molecules, nanoparticles and interfaces.

SIMULATION OF SOLID STATE INTERFACES

In cooperation with industry we simulate e.g. polymer systems at SiO2 interfaces and their cross-linking by means of force field and ab initio methods (Reaxff, CPMD, ADF, Gaussian). Areas of application are silanization and vulcanization and their chemical elementary steps. From the computer-chemical calculations, thermodynamic properties can be determined that provide information about the mechanical stability of the elastic materials.

The picture on the left shows an overview of the three components of a polymer-silica system with the polymer matrix, the silica particle as filler and the silane as bridging agent.

Antioxidants play an important role in stabilizing the material properties in such polymer systems. These organic molecules transfer hydrogen to the unwanted radical centers in the material caused by mechanical, thermal and photochemical stress. For this purpose, force-induced bond breaks are simulated and the occurring radicals are characterized.

The picture shows the Wannier orbitals of a sulfur-isoprene bond, which is broken in the course of the simulation.


EXPERIMENTAL OBSERVATION OF REACTIVE WETTING EFFECTS AND TRANSPORT MECHANISMS

Anisotropic spreading of liquid silicon on crystalline substrate
Schematic Design HT-AES

 

 

In the field of basic research, we are interested in the coupling between pattern-forming reactive wetting and anisotropic oxygen transport through interfaces only a few nanometers thick. The transport of reaction products from the interface into the environment is also important and in this context interesting analogies to the processes of chemical transport occur. Through the introduction of foreign particles, heterogeneous nucleation processes are induced and investigated.

The demanding reactive conditions are experimentally challenging. Therefore, new measuring apparatuses are developed and built to adapt analytical methods such as high-temperature video microscopy and high-temperature Auger electron spectroscopy to these conditions.

Ex situ we use electron microscopy and atomic force microscopy to visualize and measure the topography of the generated samples. In cooperation with other groups from the Faculty of Natural Sciences and Mechanical Engineering, further investigation methods are available, e.g. to elucidate the chemical composition of surfaces and boundary layers.

CONTACT

Prof. Dr. rer. nat. Jörg August Becker
Address
Callinstraße 3a
30167 Hannover
Building
Room
114
Address
Callinstraße 3a
30167 Hannover
Building
Room
114