Concept

Polytétrafluoroéthylène

Publications associées (57)

Revealing the Formation Dynamics of Janus Polymer Particles: Insights from Experiments and Molecular Dynamics

Seeded emulsion polymerization is one of the best-known methods for preparing polymer particles with a controlled size, composition, and shape. It first requires the preparation of seed particles, which are then swollen with additional monomer (the same as ...

Washington2023

Multiscale microshaping of functionally graded polymer-derived SiCN ceramics

Lorenz Hagelüken

Polymer-derived ceramics (PDCs) exhibit excellent properties and are compatible with many shaping techniques due to the liquid character of the preceramic polymers (PCPs). Furthermore, their properties are adjustable by modifying the precursor composition ...

EPFL2022

Chemo- and regio-divergent access to fluorinated 1-alkyl and 1-acyl triazenes from alkynyl triazenes

Kay Severin, Nicolai Cramer, Carl Thomas Bormann, Jin Fay Tan

The 1,1,2,2-tetrafluoroethylene unit is prevalent in bioactive molecules and functional materials. Despite being in principle a straightforward strategy to access this motif, the direct tetrafluorination of alkynes involves very hazardous or inconvenient r ...

2022

Chemical evolution of primary and secondary biomass burning aerosols during daytime and nighttime

Athanasios Nenes, Satoshi Takahama, Spyros Pandis, Amir Yazdani

Fine particulate matter (PM) affects visibility, climate, and public health. Biomass burning (BB) in the forms of residential wood burning, wildfires, and prescribed burning is a major source of primary and secondary organic matter (OM, an important fracti ...

2022

Multiscale 2D/3D microshaping of property-contrast polymer-derived SiCN

Jürgen Brugger, Lorenz Hagelüken

Polymer-derived ceramics are a unique class of materials known for their outstanding properties and versatile applicability. The liquid nature of the precursors allows easy addition of fillers in order to alter the resulting ceramics’ properties. We use a ...

2022

Nonlocal Effects Reflect the Jamming Criticality in Frictionless Granular Flows Down Inclines

Matthieu Wyart, Hugo Robin Louis Perrin

The jamming transition is accompanied by a rich phenomenology such as hysteresis or nonlocal effects that is still not well understood. Here, we experimentally investigate a model frictionless granular layer flowing down an inclined plane as a way to disen ...

AMER PHYSICAL SOC2021

Flexible Support for Gas-Lubricated Bearing Bushings

Jürg Alexander Schiffmann

Herringbone-grooved journal bearings (HGJBs) for high-speed turbo-machinery are often supported on O-rings due to their favorable stiffness and damping characteristics for stability and alignment reasons. They yield limited lifetime at high temperatures, i ...

2020

Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: systematic intercomparison of calibration methods for US measurement network samples

Satoshi Takahama, Matteo Reggente

Peak fitting (PF) and partial least squares (PLS) regression have been independently developed for estimation of functional groups (FGs) from Fourier transform infrared (FTIR) spectra of ambient aerosol collected on Teflon filters. PF is a model that quant ...

Copernicus GmbH2019

Taming the viscoelastic creep of dielectric elastomer actuators

Herbert Shea, Samuel Rosset, Alexandre Poulin

We present a simple open-loop method to suppress the viscoelastic drift of dielectric elastomer actuators (DEAs). Viscoelastic creep is one of the drawbacks of DEAs, especially when made with acrylic elastomer membranes (VHB). This leads to a time-dependen ...

SPIE-INT SOC OPTICAL ENGINEERING2019

Iron-coated polymer films with high antibacterial activity under indoor and outdoor light, prepared by different facile pre-treatment and deposition methods

César Pulgarin, Sami Rtimi, Stefanos Giannakis, Ania Schärer

In the present work, we study the fabrication of self-cleaning antibacterial surfaces, active under indoor or outdoor light. In order to obtain the highest activity with the lowest complexity we assess mild conditions of preparation (temperatures), pre-tre ...

ELSEVIER SCIENCE BV2019

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