The dynamics of interfacial slippage of entangled polystyrene (PS) films on an adsorbed layer of polydimethylsiloxane on silicon was studied from the surface capillary dynamics of the films. By using PS with different molecular weights, we observed slippage of the films in the viscoelastic liquid and rubbery solid state, respectively. Remarkably, all our data can be explained by the linear equation, J=-M∇P and a single friction coefficient, ξ, where J is the unit-width current, M is mobility, and P is Laplace pressure. For viscous films, M is accountable by using conventional formulism. For rubbery films, M takes on different expressions depending on whether the displacements associated with the slip velocity, v_{s}(∼∇P/ξ), dominate or elastic deformations induced by ∇P dominate. For viscoelastic liquid films, M is the sum of the mobility of the films in the viscous and rubbery states.
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http://dx.doi.org/10.1103/PhysRevE.99.010501 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
Crystalline organic semiconductors, recognized for their highly ordered structures and high carrier mobility, have emerged as a focal point in the field of high-performance optoelectronic devices. Nevertheless, the intrinsic unipolar properties, characterized by imbalanced hole and electron transport capabilities, have continuously represented a significant challenge in the advancement of high-performance crystalline thin-film organic light-emitting diodes (C-OLEDs). Here, a bipolar solid-solution thin film with a maintained crystal structure has been fabricated using 2-(4-(9H-carbazol-9-yl)phenyl)-1(3,5-difluorophenyl)-1H-phenanthro [9,10-d]imidazole (2FPPICz) and 4-(1-(3,5-difluorophenyl)-1H-imidazo[4,5-][1,10]phenanthrolin-2-yl)-N,N-diphenylaniline (2Fn) via a weak epitaxial growth (WEG) process, exhibiting nearly equivalent hole and electron mobilities (10-10 cm V s).
View Article and Find Full Text PDFLangmuir
January 2025
Gulliver, CNRS, ESPCI Paris, Université PSL, Paris 75005, France.
We experimentally study the formation of surface patterns in grafted hydrogel films of nanometer-to-micrometer thickness during imbibition-driven swelling followed by evaporation-driven shrinking. Creases are known to form at the hydrogel surface during swelling; the wavelength of the creasing pattern is proportional to the initial thickness of the hydrogel film with a logarithmic correction that depends on microscopic properties of the hydrogel. We find that, although the characteristic wavelength of the pattern is determined during swelling, the surface morphology can be significantly influenced by evaporation-induced shrinking.
View Article and Find Full Text PDFSci Adv
January 2025
National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China.
Revealing the momentum-resolved electronic structure of infinite-layer nickelates is essential for understanding this class of unconventional superconductors but has been hindered by the formidable challenges in improving the sample quality. In this work, we report the angle-resolved photoemission spectroscopy of superconducting LaSrNiO films prepared by molecular beam epitaxy and in situ atomic-hydrogen reduction. The measured Fermi topology closely matches theoretical calculations, showing a large Ni [Formula: see text]-derived Fermi sheet that evolves from hole-like to electron-like along and a three-dimensional (3D) electron pocket centered at the Brillouin zone corner.
View Article and Find Full Text PDFPLoS One
January 2025
School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, United Kingdom.
The assessment of biological maturation is a central topic in pediatric exercise sciences. Skeletal age (SA) reflects changes in each bone of the hand and wrist from initial ossification to the adult state. This study examined intra-observer and inter-examiner agreement is Greulich-Pyle (GP) assessments of SA in 97 male tennis players 8.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, China.
The deposition of alkali metals on oxide surfaces has garnered significant interest due to their critical role in enhancing various catalytic processes. However, the atomic-scale characterization of these structures remains elusive, owing to the complex and competing interactions among the oxygen, the alkali metals, and the metal atoms within the oxides. In this work, we grew alkali metals (Na, K, Cs) on the copper oxide films on the Cu(111) surface and found the formation of hexagonally ordered monolayer films.
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