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Polymer Physics at
Hamburg University
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Materials Science and Nanostructure at the Cutting Edge:
The age of reading tea leaves has passed. No more interpretation of scattering patterns (What does the reflection I see mean
for the nanostructure?). We have invented the method to transform scattering patterns in a way that the nanostructure becomes
visible.
The mathematical procedure is published. The computer programs are no secret.
Anyone who actually tries to interpret raw scattering patterns of distorted nanostructures by application of concepts derived
from the field of crystallography is demonstrating mediocrity. Do not expect useful insight from such work.
What is happening to the structure on the nanometer scale during melting,
crystallizing, straining, ageing, swelling of
oriented polymer materials? - We tell you the answers. Contact us and bring some (real) funds with you. Continuously we received lots of
friendly words and promises. But before it comes to funding something is cropping up every now and then. Thus we are no longer able to
travel to international congresses and pay for national congresses and urgently needed parts for our research from our salary.
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Polymer physics - that is soft matter materials science.
Soft matter is crystallizing poorly and, in general, exhibits
little order. Ubiquituous representatives of this class of materials
are polymers ("plastics").
We do not work on polymers in solution; instead we study
polymer materials in the solid state.
Tailoring Materials Properties
Nanostructure
Plastics parts are shaped with little effort - even the inner structure is
changed (sometimes too) easily. This nanostructure comprises hard (e.g. crystalline)
and soft domains of different shape and arrangement. It is an important parameter
defining materials properties. Soft domains contribute to materials ductility,
hard domains add to elasticity, respectively. Suitably combined they result in
tailored properties for, e.g., lightweight body armor.
A major issue of polymer physics is the understanding of nanostructure
evolution and its control during technical processes, aiming at tailored
polymer materials.
X-Ray Methods
We focus on the development of methods that can be used to analyse nanostructure
from corresponding X-ray patterns. In order to X-ray no part needs to be cut. But
nanostructure can only be studied using intense X-ray sources (e.g. a synchrotron).
Moreover, the recorded patterns need to be analysed.
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We investigate polymers
- under load
- during temperature treatment
- during processing
in time-resolved measurements and with spatial resolution.
We visualise the variation of the nanostructure from hard
and soft domains.
The sketch shows a test bar in a straining stage, being irradiated by X-ray.
The scattering pattern is observed on a detector placed at great distance from
the bar.
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Our expertise
- Experiments with X-rays at a synchrotron
- Development of methods
- Quantitative data analysis
- Automation by application of signal processing methods
("digital remastering") and by methods of digital image processing
(error correction)
- Correlation of structure and part properties
- Correlation of processing and nanostructure evolution
The figure exhibits the nanostructure - as automatically extracted from
the scattering pattern. A macro lattice is obvious. It comprises hard domains
in a cylindrical shape and good short-range order, but poor long-range order.
Cylinder dimensions and the distances among them can easily be determined.
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