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Publications 2021

Highlights 2021


Measurements of periodically perturbed dewetting force fields and their consequences on the symmetry of the resulting patterns

2021-rei-02.jpgWe studied the origin of breaking the symmetry for moving circular contact lines of dewetting polymer films suspended on a periodic array of pillars. There, dewetting force fields driving polymer flow were perturbed by elastic micro-pillars arranged in a regular square pattern. Elastic restoring forces of deformed pillars locally balance driving capillary forces and broke the circular symmetry of expanding dewetting holes. The observed envelope of the dewetting holes reflected the symmetry of the underlying pattern, even at sizes much larger than the characteristic period of the pillar array, demonstrating that periodic perturbations in a driving force field can establish a well-defined pattern of lower symmetry. For the presented system, we succeeded in squaring the circle. [mehr...]


Continuous Illumination of a Conjugated Polymer Causes Strong Enhancement of Photoluminescence

jp1c01837_0009.jpgWe present measurements of absorbance and photoluminescence (PL) for films of poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) as a function of temperature (T) and time (t) of illumination. While having no detectable influence on absorbance of this conjugated polymer, our experiments clearly revealed that illumination of PDOPT caused a significant increase in the PL intensity (IPL(T,t)), that is, the emission probability of PDOPT. Without illumination, we always observed a decrease in IPL with time. An increase in IPL was only detectable when the sample was illuminated. [mehr...]



Self-Seeding Procedure for Obtaining Stacked Block Copolymer Lamellar Crystals in Solution

brahim-polymers.jpgWe examined the formation of self-seeded platelet-like crystals from polystyrene-block-polyethylene oxide (PS-b-PEO) diblock copolymers in toluene as a function of polymer concentration (c), crystallization temperature (TC), and self-seeding temperature (TSS). We showed that the number (N) of platelet-like crystals and their mean lateral size (L) can be controlled through a self-seeding procedure.   [mehr...]



Formation of Stacked Three-Dimensional Polymer “Single Crystals”

ma1c00081_0006.gif

Stacks of crystalline lamellae all having a uniquely oriented hexagonal shape, referred to as “3D (three-dimensional) single crystals”, were obtained via isothermal crystallization of isotactic polystyrene at a temperature close to the melting point. The height of the stacks of lamellae reached several micrometers corresponding to hundreds of superposed lamellar crystals. We propose that the mechanism of self-induced nucleation allowed propagating the orientation of the basal lamellar crystal to all other lamellae in the stack. [mehr...]

 

Complete List 2021

Self-Seeding Procedure for Obtaining Stacked Block Copolymer Lamellar Crystals in Solution
Brahim Bessif, Thomas Pfohl and Günter Reiter. Polymers 13 (2021) 1676
Concepts of nucleation in polymer crystallization
Jun Xu, Günter Reiter, Rufina G. Alamo. Crystals 11 (2021) 304
Continuous illumination of a conjugated polymer causes strong enhancement of photoluminescence
Yaser AlShetwi, Daniel Schiefer, Michael Sommer. Günter Reiter. J. Phys. Chem. B 125 (2021) 5636–5644
Formation of Stacked Three-Dimensional Polymer “Single Crystals”
Zhixin Guo, Shouke Yan, Günter Reiter. Macromolecules 54 (2021) 4918–4925
Measurements of periodically perturbed dewetting force fields and their consequences on the symmetry of the resulting patterns
Konstantinos Roumpos, Sarah Fontaine, Thomas Pfohl, Oswald Prucker, Jürgen Rühe, and Günter Reiter. Scientific Reports 11 (2021) 13149
Changes in surface free energy and surface conductivity of carbon nanotubes/polyimide nanocomposite films induced by UV irradiation
Baode Zhang, Marialaura Clausi, Barbara Heck, Susanna Laurenzi, Gabriella Santonicola, Janis Kleperis, Andris Antuzevičs, Guenter Reiter, Andrey Aleshin, Anatoly Lobach. ACS Appl. Mater. Interfaces 13 (2021) 24218–24227
Surface-modified elastomeric nanofluidic devices for single nanoparticle trapping
Deepika Sharma, Roderick Y. H. Lim, Thomas Pfohl and Yasin Ekinci. Microsystems & Nanoengineering 7 (2021) 46
Optimization of Nanofluidic Devices for Geometry-Induced Electrostatic Trapping
Deepika Sharma, Roderick Y. H. Lim, Thomas Pfohl, and Yasin Ekinci. Part. Part. Syst. Charact. 2021, 38, 2000275
Tuning topography and patterns of thin polymer films on structured substrates
Konstantinos Roumpos. Inauguraldissertation der Fakultät für Mathematik und Physik 2021. DOI: 10.6094/UNIFR/194127
High-throughput injection molding of transparent fused silica glass
Markus Mader, Oliver Schlatter, Barbara Heck, Andreas Warmbold, Alex Dorn, Hans Zappe, Patrick Risch, Dorothea Helmer, Frederik Kotz, Bastian E. Rapp. Science 372 (2021) 182-186
A new growth process for crystalline ultra-thin layers of conjugated oligomers used in field-effect transistor applications
Sven Renkert, Sadiara Fall, Sajedeh Motamen, Thibaut Jarrosson, Françoise Serein-Spirau, Thomas Heiser, Laurent Simon, Günter Reiter, Jean-Luc Bubendorff. Applied Surface Science 539 (2021) 148024
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