You are here: Home Publications
Document Actions

Publications

bibliothek-720x.jpgwx121.jpg

Select the year of publication...

2016-2018 2019-2021 2022-2024 2025-2026
2004-2006  2007-2009 2010-2012  2013-2015
before 1990 1991-1995  1996-2000 2001-2003

 

 ...or go to the

advanced search form.

 

Recent Publications


Spatiotemporal Sequence of Interdependent Nucleation Mechanisms in Ultrathin Polymer Films

Da Huang, Rana Bakhshi, Raoul M. D'Anselme, Günter Reiter. Macromolecules, published online

Employing defined starting conditions of ultrathin molten poly(ethylene oxide) films on model solid substrates, we investigated the spatiotemporal sequence of interdependent mechanisms of crystal nucleation. Due to the limited number and the preferred conformation of polymer chains parallel to the substrate, primary nucleation favored edge-on lamellar crystals, which indirectly induced other subsequent nucleation pathways, enabled through the molten polymer chains accumulated at their peripheral fold surfaces. Both additional edge-on lamellar crystals and branched flat-on lamellar crystals were initiated. For long-chain polymers, spatial correlations between lamellar crystals across intervening noncrystalline regions were established through polymer chains incorporated within neighboring lamellae. (more...)


Nonmonotonic Variation of the Preferential Orientation of Lamellar Crystals in Films of Cold-Crystallized Poly(l-lactide) of Increasing Thickness and Molecular Weight

Decai Lin, Zebin Su, Yuxiang Chen, Jianquan Xu, Günter Reiter, Cuiyun Zhang, Xinping Wang. Macromolecules  59 (2026) 4970–4981

Using infrared reflection–absorption spectroscopy and atomic force microscopy, we revealed that polymer–substrate interactions, chain length, and film thickness critically influenced the morphology and orientation of lamellar crystals of poly(l-lactide) (PLLA) grown at a constant temperature. In contrast to the often-observed monotonic change from preferentially flat-on to edge-on crystals upon increasing film thickness, an unprecedented nonmonotonic change in the dominating orientation of lamellar crystals from edge-on to flat-on and back to edge-on was observed. In the thinnest films, size confinement and adsorption-induced alignment of the chains favored the nucleation and growth of edge-on lamellar crystals. Enhanced polymer–substrate interactions promoted the formation of edge-on lamellar crystals in the thinnest films with a higher molecular weight. (more..)


Properties of Charged Conjugated Polymers Deposited by Electrospraying on Substrates with an Insulating Oxide Layer

Anmol Arya, Solomon L. Joseph, Francois Vonau, Jean-Luc Bubendorff, Silvia Siegenführ, Laurent Simon, Günter Reiter. J. Phys. Chem. C 2026, 130, 5536–5546

In the course of electrospraying in a vacuum, polymers acquire electric charges, which are distributed along their backbone. Here, we demonstrate that these charges have a strong impact on the molecular ordering and spectroscopic properties of conjugated polymers when deposited on substrates with an insulating oxide layer. To this end, we electrosprayed varying amounts of poly(3-hexylthiophene) (P3HT) onto silicon substrates with oxide layers of different thickness. The resulting morphologies were explored by atomic force microscopy. The corresponding spectroscopic properties, including their changes in time upon illumination, were derived from photoluminescence (PL) measurements. On insulating substrates, charges were retained on the polymer chains, causing long-range electrostatic repulsion and the formation of largely separated droplet-like objects containing multiple chains. These objects exhibited significant PL intensities for photons with a wavelength (λ) less than ca. 600 nm, suggesting the lack of π–π stacking interactions between P3HT chains. (more...)


Reversible Metamorphosis of a Conjugated Polymer Induced by Photoexcitation

Solomon Joseph, Anmol Arya, Günter Reiter. Advanced Photonics Research 7 (2026) e202500311

Optoelectronic properties of materials are frequently examined through spectroscopic tools based on the absorption and emission of (visible) photons. Typically, one assumes that these transient characterization processes do not cause observable change of these properties because of the low power of the employed light sources. However, for flexible conjugated polymers in a medium of low viscosity, it is decidedly unclear whether photoexcitation of electrons on the backbone of a long polymer chain has an influence on macromolecular conformations and the corresponding intermolecular interactions. Here, we provide clear experimental evidence that continuous absorption of photons progressively causes persistent changes in the spectroscopic properties of conjugated polymers, accompanied by microscopically observable changes in their spatial distribution within a low-viscosity matrix. By contrast, all these changes were completely absent in nonilluminated parts of the same sample.(more...)


Temperature dependence of crystal – melt coexistence for supported polyethylene filaments

Da Huang, Thorsten Hugel, Bizan N. Balzer, Günter Reiter. Nature Communications 16 (2025) 11127

The broken symmetry of molecular interactions at interfaces is causing that crystals are often covered by a thin liquid layer of their own melt. Such crystal–melt coexistence can be related to phenomena of surface premelting, secondary nucleation and melting point depression, particularly important for small systems. Here, we employed intermittent-contact mode atomic force microscopy imaging on nanoscopic semi-cylindrical filaments of polyethylene on a substrate to observe that these filaments contained a crystalline core bounded by molten regions of rather uniform width,  W_soft= (9 ± 2) nm at room temperature, which increased reversibly with temperature T. Filaments smaller than ca. 2∙W_soft (T) were completely molten. The values of W_soft (T) compared favorably with theoretically predicted characteristic length scales in the context of nucleation, surface premelting and the melting point depression of finite size crystals. Altogether, we show that these three phenomena are related and dominated by the intermolecular forces acting at crystal surfaces.(more...)

 

List of Publications

Non-equilibrium Properties of Thin Polymer Films
Sivasurender Chandran, Günter Reiter. In Matyjaszewski et al. (Eds.): Macromolecular Engineering: From Precise Synthesis to Macroscopic Materials and Applications, 4 Volumes, 2nd ed. Edition, Wiley-VCH Verlag GmbH, 2022. ISBN 9783527344550
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
Morphological transitions in langmuir films of a diblock copolymer from polyethylene glycol and poly-L-lactide
Emna Khechine. Inaugural-Dissertation zur Erlangung des Doktorgrades der Fakultät für Chemie und Pharmazie, 2021
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
Formation of large polymer crystals from metastable solutions
Tianyu Wu. Inauguraldissertation der Fakultät für Chemie und Pharmazie 2020, DOI: 10.6094/UNIFR/167415
Exploring pathways to equilibrate Langmuir polymer films
Abhijna Das, Sebastian Noack, Helmut Schlaad, Günter Reiter, Renate Reiter. Langmuir 36 (2020) 8184–8192
Energy transport and light propagation mechanisms in organic single crystals
Bernd Wittmann, Stephan Wiesneth, Sajedeh Motamen, Laurent Simon, Françoise Serein-Spirau, Günter Reiter, and Richard Hildner. Journal of Chemical Physics 153 (2020) 144202
Large quantum efficiency enhancements of pristine conjugated polymer MEH-PPV by interlayer polymer diffusion
Po-Tsun Chen, Ya-Wei Yang, Günter Reiter, Arnold C.-M. Yang. Polymer 204 (2020) 122753
Formation of Needle-like Poly(3-hexylthiophene) Crystals from Metastable Solutions
Tianyu Wu, Thomas Pfohl, Sivasurender Chandran, Michael Sommer and Günter Reiter. Macromolecules 53 (2020) 8303–8312
Rheological Properties of Blends of Isotactic Polystyrene–Isotactic Poly(para-methylstyrene) Films Derived from a Comparative Dewetting Study
Austine Amukayia Mulama, Konstantinos Roumpos, Pradipkanti Lairenjam, Andrew Oduor, Günter Reiter. Macromolecules 53 (2020) 9122–9130
Dewetting-Induced Alignment and Ordering of Cylindrical Mesophases in Thin Block Copolymer Films
Heng Zhang, Binghua Wang, Gang Wang, Changyu Shen, Jingbo Chen, Günter Reiter, Bin Zhang. Macromolecules 53, (2020) 9631–9640
Estimation of the Size of Critical Secondary Nuclei of Melt-Grown Poly(l-lactide) Lamellar Crystals
Shujing Zhang, Baohua Guo, Günter Reiter, Jun Xu. Macromolecules 53 (2020) 3482–3492
Translating molecular relaxations in non-equilibrated polymer melts into lifting macroscopic loads
Farzad Ramezani, Jörg Baschnagel, and Günter Reiter. Phys. Rev. Materials 4 (2020) 082601
Personal tools