Scratch-Resistant Hydrophobic Coating with Supramolecular-Polymer Co-Assembly

Está pagada la tasa. Se trata de un artículo de open access. La información que debe recogerse en Digitum es la siguiente: ©2023 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH. This manuscript version is made available under the CC-BY-NC 4.0 license https://creativecommons.org/licenses/by-nc/4.0/ This document is the Published Manuscript version of a Published Work that appeared in final form in Advanced Functional Materials. To access the final edited and published work see https://doi.org/10.1002/adfm.202309140Supramolecular assembly for superhydrophobic coatings is known for its efficiency and efficacy. However, the mechanical fragility of the coatings limits their use as coating materials. Herein, the combination of (±)-N,N'-(trans-cyclohexane-1,2-diyl)-bis(perfluorooctanamide) CF7, a cyclohexyl diamide-based low molecular weight gelator, with acrylate polymers for the generation of semi-transparent omniphobic coatings with significantly enhanced scratch proofness is presented. CF7 has shown the ability to self-assemble in common solvents into highly entangled fibrous networks with extreme water repellency. The incorporation of covalent polymers, specifically poly(methyl methacrylate) (PMMA) and poly(trifluoroethyl methacrylate) (PTFEMA), helps to fixate the supramolecular CF7 fibers without interfering with the self-assembled structures. The resulting coatings, namely CF7/PMMA and CF7/PTFEMA, show significantly improved mechanical resistance as well as optical transparency while maintaining excellent water and oil repellency. Furthermore, the homogeneity of the coating in bulk is confirmed by depth profiling of the 3D distribution of the components using time-of-flight secondary ion mass spectrometry imaging, which turns out to be an essential technique in order to characterize such materials

Scratch-Resistant Hydrophobic Coating with Supramolecular-Polymer Co-Assembly

Supramolecular assembly for superhydrophobic coatings is known for its efficiency and efficacy. However, the mechanical fragility of the coatings limits their use as coating materials. Herein, the combination of (±)-N,N'-(trans-cyclohexane-1,2-diyl)-bis(perfluorooctanamide) CF7, a cyclohexyl diamide-based low molecular weight gelator, with acrylate polymers for the generation of semi-transparent omniphobic coatings with significantly enhanced scratch proofness is presented. CF7 has shown the ability to self-assemble in common solvents into highly entangled fibrous networks with extreme water repellency. The incorporation of covalent polymers, specifically poly(methyl methacrylate) (PMMA) and poly(trifluoroethyl methacrylate) (PTFEMA), helps to fixate the supramolecular CF7 fibers without interfering with the self-assembled structures. The resulting coatings, namely CF7/PMMA and CF7/PTFEMA, show significantly improved mechanical resistance as well as optical transparency while maintaining excellent water and oil repellency. Furthermore, the homogeneity of the coating in bulk is confirmed by depth profiling of the 3D distribution of the components using time-of-flight secondary ion mass spectrometry imaging, which turns out to be an essential technique in order to characterize such materials

Poly[[μ2-1,4-bis­(4,5-dihydro-1,3-oxazol-2-yl)benzene-κ2 N:N′]di-μ2-chlorido-cadmium]

In the title coordination polymer, [CdCl2(C12H12N2O2)]n, the CdII ion, situated on an inversion center, is coordinated by four bridging Cl atoms and two N atoms from two 1,4-bis­(4,5-dihydro-1,3-­oxazol-2-yl)benzene (L) ligands in a distorted octa­hedral geometry. Each L ligand also lies across an inversion center and bridges two CdII ions, forming infinite two-dimensional recta­ngular layers running parallel to (010)

PHYSIOLOGICAL AND ELECTROMYOGRAPHIC RESPONSES AT THREE LEVELS OF BICYCLE SEAT HEIGHT

Recently, bicycle riding has become one of the most popular exercises. As the use time increased, the risk of pedalling injury raised. Holmes (1994) indicated that inappropriate bicycle saddle height could result in lower limbs injuries. The motivation of this study was to find out the best riding position that could effectively use energy from the physiology and electromyography measures. The oxygen consumption (VO2), heart rate (HR), respiratory exchange ratio (RER) and the muscle activity (electromyography, EMG) from rectus femoris (RF) and biceps femoris (BF) of lower limb were collected during a 6 min cycling trail in three different heights of bicycle saddle. The purpose of this study was to compare the effects of three different types of bicycle seat heights and different perspectives of muscle activity and physiology’s parameters

Signs of outflow feedback from a nearby young stellar object on the protostellar envelope around HL Tau

HL Tau is a Class I-II protostar embedded in an infalling and rotating envelope and possibly associated with a planet forming disk, and it is co-located in a 0.1 pc molecular cloud with two nearby young stellar objects. Our ALMA observations revealed two arc-like structures on a 1000 au scale connected to the disk, and their kinematics could not be explained with any conventional model of infalling and rotational motions. In this work, we investigate the nature of these arc-like structures connected to the HL Tau disk. We conducted new observations in the 13CO and C18O (3-2; 2-1) lines with JCMT and IRAM 30m, and obtained the ACA data with the 7-m array. With the single-dish, ACA, and ALMA data, we analyzed the gas motions on both 0.1 pc and 1000 au scales in the HL Tau region. We constructed new kinematical models of an infalling and rotating envelope with the consideration of relative motion between HL Tau and the envelope. By including the relative motion between HL Tau and its protostellar envelope, our kinematical model can explain the observed velocity features in the arc-like structures. The morphologies of the arc-like structures can also be explained with an asymmetric initial density distribution in our model envelope. In addition, our single-dish results support that HL Tau is located at the edge of a large-scale (0.1 pc) expanding shell driven by the wind or outflow from XZ Tau, as suggested in the literature. The estimated expanding velocity of the shell is comparable to the relative velocity between HL Tau and its envelope in our kinematical model. These results hints that the large-scale expanding motion likely impacts the protostellar envelope around HL Tau and affects its gas kinematics. We found that the mass infalling rate from the envelope onto the HL Tau disk can be decreased by a factor of two due to this impact by the large-scale expanding shell.Comment: Accepted by A&

Existence theorems for a crystal surface model involving the p-Laplace operator

The manufacturing of crystal films lies at the heart of modern nanotechnology. How to accurately predict the motion of a crystal surface is of fundamental importance. Many continuum models have been developed for this purpose, including a number of PDE models, which are often obtained as the continuum limit of a family of kinetic Monte Carlo models of crystal surface relaxation that includes both the solid-on-solid and discrete Gaussian models. In this paper we offer an analytical perspective into some of these models. To be specific, we study the existence of a weak solution to the boundary value problem for the equation - \Delta e^{-\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right)}+au=f, where $p>1, a>0$ are given numbers and $f$ is a given function. This problem is derived from a crystal surface model proposed by J.L.~Marzuola and J.~Weare (2013 Physical Review, E 88, 032403). The mathematical challenge is due to the fact that the principal term in our equation is an exponential function of a p-Laplacian. Existence of a suitably-defined weak solution is established under the assumptions that $p\in(1,2], \ N\leq 4$, and $f\in W^{1,p}$. Our investigations reveal that the key to our existence assertion is how to control the set where -\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right) is $\pm\infty$

Interfaces with Fluorinated Amphiphiles: Superstructures and Microfluidics

The present mini-review discusses recent developments in research on interfacial phenomena of fluorinated amphiphiles, focusing on applications that exploit the unique and manifold interfacial properties associated with these amphiphiles. Most notably, fluorinated amphiphiles form stable aggregates with often distinctly different morphologies than their non-fluorinated counterparts. Consequently, fluorinated surfactants have found wide use in high-performance applications such as microfluidic-assisted screening. Additionally, their fluorine-specific behaviour at the solid/liquid interface, such as the formation of superhydrophobic coatings after deposition on surfaces, will be discussed. As fluorinated surfactants and perfluorinated materials in general pose potential environmental threats, recent developments in their remediation based on their adsorption onto fluorinated surfaces will be evaluated