Plenarvorträge - DPG-Tagungen

Chemische Physik und Polymerphysik Montag
Fachsitzungen
– Haupt-, Kurzvorträge und Posterbeiträge –
CPP 1 Polymer Surfaces I
Zeit: Montag 09:30–10:45 Raum: H 37
Hauptvortrag CPP 1.1 Mo 09:30 H 37
Thin, nanostructured block copolymer films — •Christine M.
Papadakis — Fakultät für Physik und Geowissenschaften, Universität
Leipzig, now at Physik Department, Technische Universität München
Block copolymer films can be used for patterning surfaces on a submicrometer
length scale. In order to understand the surface structures
observed as well as their stability and their response to outer stimuli, it
is important to gain knowledge both on the surface structures as well
as on the inner film structure. The combination of direct visualization
of the surface texture by atomic force microscopy with scattering methods
elucidating the inner film structure has proven to give a wealth of
information. By means of grazing-incidence small-angle X-ray scattering
(GISAXS), structures normal to the substrate as well as lateral structures
can be detected simultaneously. In addition, time-resolved GISAXS
measurements can be used to study the structural changes of the films
upon outer stimuli in-situ. In my talk, I will present results on thin films
of a series of polystyrene-polybutadiene diblock copolymers, where we
have found a previously unknown molar-mass dependence of the lamellar
orientation. The structural changes of he films when subjected to a
vapor atmosphere were monitored in-situ.
CPP 1.2 Mo 10:00 H 37
Volume Phase Transition of PNIPAM-Microgel Paricles Studied
with Laser-AFM — •Lothar Zitzler 1 , Frieder Mugele 1 ,
and Stephan Herminghaus 1,2 — 1 Angewandte Physik, Universität
Ulm, Albert-Einstein-Allee 11, 89081 Ulm — 2 Max-Planck-Institut für
Strömungsforschung, Bunsenstraße 10, 37073 Göttingen
Poly(N-isopropylacrylamide) (PNIPAM) is a polymer with a lower critical
solution temperature (LCST) of TLCST ≈ 32˚C. It shows a conformational
change from a coil to a globule state upon increasing the temperature
above TLCST. Here we present AFM-studies (in aqueous environment)
of PNIPAM-co-poly(vinyl acetic acid) microgel particles adsorbed
on glass substrates. Like in solutions the adsorbed particles also show
a pronounced change in volume of approximately 200% with respect to
the globular state. The different elastic properties of the particles in the
coil and globular states could be distinguished clearly in amplitude- and
phase-distance curves, obtained by AFM in Tapping Mode.
To study the dynamics of this coil to globule transition we combined the
AFM with an intense cw-laser (5W at 532nm). We generated laser pulses
of variable width (10ns-100µs) with an acousto-optical modulator. The
laser pulses were used to trigger the volume phase transition by heating
the particles above TLCST. By synchronizing the laser pulses with
CPP 2 Polymer Surfaces II
the cantilever oscillation and by varying the relative time delay one can
obtain information on the dynamics of the phase transition.
CPP 1.3 Mo 10:15 H 37
Influence of the chain microstructure in the surface properties
of polyketone terpolymers — •Sabine Hild 1 , Othmar Marti 1 ,
Frank Hollmann 2 , David Perez Foullerat 2 , and Bernhard
Rieger 2 — 1 Experimental Physics, University of Ulm, Albert-Einstein-
Allee 11, 89081 Ulm — 2 Inorganic Chemistry II, University of Ulm,
Albert-Einstein-Allee 11, 89081 Ulm
Terpolymers of carbonmonoxide (CO), ethene and propene combine
unique physical properties with intrinsic hydrophilic properties. Tailoring
the chain microstructure of such polyketones lead to polymeric materials
with adjustable mechanical properties. The aim of this study is
to investigated if also surface properties, resp. the surface energy, can be
influenced by varying the block structure of the copolymers. For this purpose
ethylene-CO-propylene-CO-(ECO-PCO) and ethylene-CO-hexene-
CO-(ECO-HCO) terpolymers with similar amount of ECO but different
block length have been synthesized. This results in copolymers featuring
either a triblock or multiblock structure. The surface morphology of this
terpolymers is investigated by Scanning Force Microscopy. The surface
tension has been estimated by from surface tension measurement. It has
been found, that if the ECO content is higher than 50 percent the surface
properties are determined by the microstructure of the ECO phase.
CPP 1.4 Mo 10:30 H 37
AFM-studies of layered Au/hexaphenyl nanofiber systems —
•Laxman Kankate 1 , Frank Balzer 1 , Horst Niehus 1 , and Horst-
Günter Rubahn 2 — 1 Humboldt-Universität zu Berlin, Institut für
Physik / ASP — 2 SDU Odense, Fysisk Institut, Denmark
In this paper we study in detail the growth of parahexaphenyl
nanofibers on ultrathin Au layers on mica. We use fluorescence microscopy
and atomic force microscopy to obtain the size distribution and
the alignment of the nanofibers. As a function of the thickness of the
Au layer in the range between 1 and 5 nm it is observed that the alignment
of the fibers decreases, whereas for thicker Au films no alignment
at all with the mica electric surface dipoles has been found. The mean
length of the fibers decreases from several ten µm to 1 µm, but their
mean height increases from 50 nm to 300 nm. Such sandwich systems of
organic and metallic constituents are important model systems for future
nanoelectronic applications.
Zeit: Montag 11:00–12:30 Raum: H 37
CPP 2.1 Mo 11:00 H 37
Scanning thermal microscopy for investigation of mechanical
properties of thin polymer films — •Martin Hinz 1 , Andreas
Kleiner 1 , Sabine Hild 1 , Othmar Marti 1 , Urs Dürig 2 , Bernd
Gotsmann 2 , Ute Drechsler 2 , Peter Vettiger 2 , and Tom R. Albrecht
2 for the IBM Research Division, Zurich Research Laboratory,
Switzerland collaboration — 1 Department of Experimental Physics, University
of Ulm, D-89069 Ulm — 2 IBM Research Division, Zurich Research
Laboratory, CH-8803 Rüschklikon
Mechanical properties of bulk polymers have been investigated by different
methods over decades, but in recent times the mechanics of thin
polymer films became of large interest. Scanning Force Microscopy (SFM)
provides a possibility to probe mechanical properties on nanometer scale.
In this study Scanning thermal microscopy (SThM) is applied to investigate
the temperature dependent indentation process of a pulse heated
SFM-tip (heating pulse less than 100 Mikroseconds) with tip temperatures
between 300 and 500 ◦ C on Polymethylmethacrylate films of 35
nm thickness which were produced by spin-coating on Silicon substrates.
Additional application of an electro-static force acting between tip and
sample enhances the indentation process. Additionally these experiments
are carried out on samples heated on a heating device. The remanent topography
is analysed as function of tip and sample temperature, heating
pulse duration and electrostatic force.
CPP 2.2 Mo 11:15 H 37
Homo- and heteropolymer adsorption onto homogeneous
and chemically structured surfaces: the role of correlations
— •Alexey Polotsky, Andreas Degenhard, and Friederike
Schmid — Universität Bielefeld, Fakultät für Physik, Universitätsstraße
25, 33615 Bielefeld
Using a variational approach, an analytical theory of adsorption was