Plenarvorträge - DPG-Tagungen

Chemische Physik und Polymerphysik Dienstag
orientation (parallel or perpendicular to the substrate) can be controlled
by block copolymer molar mass [1].
For low angles of incidence, the scattering intensity is maximum and
details are most pronounced. This results in short measuring times, thus
allowing for time-resolved measurements as well [2]. Interpreting the twodimensional
GISAXS maps, the refraction of the X-rays at the surface of
the polymer film as well as their reflection by the substrate need to be
taken into account. This is possible by calculating the scattering cross
section in the framework of the distorted-wave Born approximation. Both
for the case of parallel and perpendicular lamellae, the model compares
well with the experimental results.
[1] P. Busch et al., Macromolecules 36, 8717 (2003).
[2] D.-M. Smilgies et al., Synchr. Rad. News 15, 35 (2002).
CPP 15.14 Di 17:00 B
Charakterisierung von Ruß-Kautschuk-Mischungen mittels
dielektrischer Spektroskopie — •Jöerg Ludwig und Dietmar
Göritz — Universitätsstraße 31, 93040 Regensburg
Zur Charakterisierung von Ruß-Kautschuk-Mischungen wurde eine
modifizierte dielektrische Meßmethode entwickelt. Hierbei werden neben
der eigentlichen Probe zwei zusätzliche Isolierschichten in den Meßkondensator
eingebracht. Dadurch wird die Reproduzierbarkeit der Ergebnisse
erheblich verbessert.
Anhand einer auf dieses System angepaßten Modellfunktion können
Parameter gewonnen werden, die das dielektrische Verhalten der jeweiligen
Mischung beschreiben. Aus diesen Parametern wiederum sind Informationen
hinsichtlich der inneren Struktur der Mischungen zu erhalten.
So kann z. B. die Dicke von gebundenen Kautschukschichten zwischen
perkolierenden Aggregaten abgeschätzt werden.
Untersucht wurde eine Reihe von Rußen, die sich in den üblichen Kenngrößen
stark unterscheiden. Die Probenserie für jede Rußsorte besteht
sowohl aus perkolierten als auch aus nicht perkolierten Mischungen. Die
Ergebnisse für sämtliche Ruße und Füllgrade können in einem einheitlichen
Rahmen interpretiert werden.
CPP 15.15 Di 17:00 B
Investigation of temperature dependent mechanical properties
of thin polymer films by AFM — •Andreas Kleiner 1 , Martin
Hinz 1 , Sabine Hild 1 , Othmar Marti 1 , Urs Duerig 2 , Bernd
Gotsmann 2 , and Tom R. Albrecht 2 — 1 Dept. of Exp. Physics, University
of Ulm, 89069 Ulm — 2 IBM Research Division, Zurich Research
Laboratory, CH-8803 Rueschlikon
Atomic Force Microscopy provides the possibility to probe mechanical
properties on nanometer scale. Combining the AFM with a heating
device for sample temperatures up to 420 K enables to investigate mechanical
properties and the thermal stability of nanostructures on thin
films at temperatures below and above the glass transition. In this study,
polymethylmethacrylate films with a molecular weight of 350 kg/mol and
a bulk glass transition temperature of 388 K are used, prepared by spincoating
on silicon substrates. The indentation behavior of a AFM tip
gives characteristic quantities like stiffness or the energy of hysteresis. In
addition to these force curve measurements, the thermal stability of the
nanostructures is determined by measuring the time evolution of the topography.
The velocity of the observed polymer relaxation as function of
the sample temperature reveals clearly the glass transition of the PMMA
film.
CPP 15.16 Di 17:00 B
Adhesion behavior of poly(urethane) foam on thermoplastics
— Karsten Busse, Nasir Mahmood, Jörg Kressler, Karsten
Busse, Nasir Mahmood, and •Jörg Kressler — Fachbereich Ingenieurwissenschaften,
Martin-Luther-Universität Halle-Wittenberg
Detailed characterization of polymer surface properties under structural
and morphological aspects is a high priority activity In our study
three formulations of poly(urethanes) are foamed in contact with different
thermoplastic materials. A thin PU-film at the interface is responsible
for the adhesion behaviour which is investigated XPS, ToF-SIMS, TEM,
NR and other methods. It was found that silicon oil remains on the foam
side after skinning from TP and parts of the foam are linked to the TP
surface. The thin film at the interface is regularly structured with alternating
layers with a typical thickness of 250-300 nm.
CPP 15.17 Di 17:00 B
EFFECT OF CROSS-LINKING AND REDUCED DIMEN-
SIONS ON THE INTERNAL FRICTION IN POLYMERS —
•Tatjana Haramina, Hans-Georg Brion, and Reiner Kirchheim
— Institut fuer Materialphysik, Uni-Goettingen, Tammanstr. 1, D-37077
Goettingen
The capacity of materials to damp out vibrations (internal friction)
is a function of a time lag between stress and strain and is related to
anelastic strain. The anelastic strain of polymer materials results from
sliding of chains, movements of segments and side groups. This internal
friction can be observed by means of mechanical spectroscopy.
The vibrating reed apparatus is developed to measure the damping of
supported amorphous polymer films. The damping is observed at about
520Hz at the temperature range from 300K to 500K. The relaxation processes
lead to peaks in mechanical spectra.
Photo-cross-linking of Poly(Vinyl Cinnamate) should decrease mobility
of polymer chains and influence the internal friction. The opposite effect
is expected from thin polymer films, where because of the big influence
of the opened surface the molecular mobility should increase.
CPP 15.18 Di 17:00 B
Domain structure of novel amphiphilic polymers in bulk and
in thin films — •Sofiya Raleva 1 , Bernd Stühn 1 , Karsten
Busse 2 , Jörg Kressler 2 , Holger Kautz 3 , and Holger Frey 4
— 1 Institute of Solid State Physics, Technische Universität Darmstadt,
D-64289 Darmstadt — 2 Department of Engineering Science, Martin-
Luther-University Halle-Wittenberg, D-06099 Halle — 3 Institute of
Macromolecular Chemistry, University of Freiburg, D-79104 Freiburg
— 4 Institute of Organic Chemistry, Johannes Gutenberg University,
D-55128 Mainz
We have investigated novel amphiphilic polymers with linear and hyperbrached
architecture. One series of amphiphiles are linear blockcopolymers
of PEO and Perfluorohexylethylmethacrylate (PFMA). A second
series are linear-dendritic poly(propylene oxide)-polyglycerol surfactants.
Langmuir-Blodgett films from these materials were deposited from chloroform
solutions with concentration 2 mg/ml onto silicon substrates at
room temperature and at a surface pressure of 35 mN/m.
Their structural properties were studied using X-ray reflection. The
results provide information on film thickness, surface roughness and electron
density variation perpendicular to the film surface. Layered structures
were found for most samples. The bulk structure was determined
using small angle X-ray scattering in Kratky geometry. Layered as well
as three dimensional structures were found. We compare the results with
the bulk properties of the materials in particular with respect to the
stability of the thin films.
CPP 15.19 Di 17:00 B
Crystallization of poly(ethylene-co-octene) studied by timedependent
polarized and depolarized light scattering —
•Takahiko Kawai and Gert Strobl — Fakultät für Physik,
Universität Freiburg, Freiburg, Germany
Isothermal crystallization of poly(ethylene(0.86)-co-octene(0.14)) from
the melt was studied by time-resolved simultaneous vv(polarized) and
hv(depolarized) light scattering measurements. The scattering pattern
showed that poly(ethylene-co-octene) formed spherulite independing on
the crystallization temperature. The power law of the forward scattering
intensity I0 was 3.5, which seemed to be quite unusual for the normal
spherulitic growth(one expects I0 ∼ t 6 ). At low crystallization tempera-
ture, both I vv
0 and Invariant Q vv goes over maximum as expected from
theory, while two step increase was observed in Q vv at high temperature.
It implies that densification occurs prior to the formation of crystals.
CPP 15.20 Di 17:00 B
Rigid amorphous fraction and reversing melting of semicrystalline
polypropylene — •Heiko Huth, Dmitry Mordvintsev,
and Christoph Schick — Universität Rostock, Fachbereich Physik,
Universitätsplatz 3, 18051 Rostock
For semicrystalline polymers the observed relaxation strength at glass
transition is often significantly smaller than expected assuming a two
phase model with crystalline and non-crystalline fraction. This observation
leads to the three phase model introducing the rigid amorphous
fraction (RAF) as a third fraction beside crystalline and non-crystalline
fraction. This RAF is non-crystalline and in a glassy state at temperatures
above the common glass transition. The RAF does not contribute to
the heat of fusion or X-ray crystallinity nor to the relaxation strength at