Selective desorption of organophosphonates on chemically functionalized titanium by Direct Laser Patterning

Surface functionalization based on organophosphonate molecules and Direct Laser Patterning (DLP) technique both allow to design chemically patterned titanium surfaces devoted to biomaterial engineering. Ultrapolished surfaces of commercially pure titanium were modified with 16-phosphonohexadecanoic acid and octadecylphosphonic acid. The DLP technique with a green pulsed laser was applied to selectively desorb the organophosphonate molecules on the functionalized titanium surfaces. Three regimes of laser ablation were found on the bare titanium surfaces as the ratio between the spot diameter and the interspot distance. Finally, the organophosphonate functionalized titanium surfaces subjected to DLP revealed different wettability domains with minimum impact on the roughness, validated by XPS, AFM and ESEM.This study was supported by the “Ministry of Science and Innovation” (project MAT2011-23339) and by the “Junta de Andalucı́a” (projects P08-FQM-4325, P09-FQM-4698 and P10-FQM-5977)

Surface activity and collective behaviour of colloidally stable Janus-like particles at the air-water interface

This work was supported by MINECO, MAT2010-15101 and MAT2011-23339 projects (Spain) and by “Junta de Andalucía” and FEDER under project P10-FQM-5977.In this work we report an experimental study on the surface activity and the collective behaviour of colloidally stable Janus-like silver particles at the air-water interface. The colloidal stability of silver nanoparticles has been enhanced using different capping ligands. Two polymers coated the silver particles: 11-mercaptoundecanoic acid and 1-undecanthiol. These capping ligands adsorbed onto the particle surface are spontaneously rearranged at the air-water interface. This feature leads to Janus behaviour in the silver particles with amphiphilic character. The surface activity of the silver particles at the air-water interface has been measured using pendant drop tensiometry. The Janus-like silver particles revealed a surface activity similar to that shown by conventional amphiphilic molecules but at much larger area per particle. The variation of the surface pressure with the area per particle was described properly using the Frumkin isotherm up to the collapse state. Furthermore, oscillating pendant drop tensiometry provided very useful data on the rheological properties of Janus particle monolayers; these properties depended on the lateral interactions between particles and were closely related to the monolayer microstructure. We revealed the close relationship between the collective behavior and the surface activity of Janus-like silver particles.MINECO MAT2010-15101, MAT2011-23339Junta de AndalucíaFEDER P10-FQM-597

Automation of an atomic force microscope via Arduino

The Dimension 3000 AFM used in this work was kindly donated by Prof. Nicholas D. Spencer, and facilitated by Prof. Lucio Isa, and Dr. Shivaprakash N. Ramakrishna, from ETH-Zurich. We thank Prof. David Cuartielles for encouraging us to publish this work in this special issue on Arduino Science Hardware. We also thank Llorenc Mercadal Fernandez for frutiful discussions and ideas, and the BiblioMaker unit in the Faculty of Sciences of the University of Granada for their help in 3D printing the gears used here. MAFR acknowledges support by the project PID2020-116615RA-I00 funded by MCIN/AEI/10.13039/501100011033, and the EMERGIA grant with reference EMC21_00008 funded by Consejeria de Universidad, Investigacion e Innovacion de la Junta de Andalucia, and by FEDER "ERDF A way of making Europe". JGGF and CLMM acknowledge support from grant A1S35536 by Conacyt Mexico.The Atomic Force Microscopy is a very versatile technique that allows to characterize surfaces by acquiring topographies with sub-nanometer resolution. This technique often overcomes the problems and capabilities of electron microscopy when characterizing few nanometers thin coatings over solid substrates. They are expensive, in the half million dollar range for standard units, and therefore it is often difficult to upgrade to new units with improved characteristics. One of these improvements, motorization and automation of the measurements is very interesting to sample different parts of a substrate in an unattended way. Here we report a low cost upgrade under 60 $ to a Dimension 3000 AFM based on a control unit using an Arduino Leonardo. It enables to acquire dozens or hundreds of images automatically by mimicking keyboard shortcuts and interfacing the AFM PCI card.MCIN/AEI PID2020-116615RA-I00Consejeria de Universidad, Investigacion e Innovacion de la Junta de Andalucia EMC21_00008Marie Curie ActionsConsejo Nacional de Ciencia y Tecnologia (CONACyT) A1S3553

Ice adhesion of PDMS surfaces with balanced elastic and water-repellent properties

This research was supported by the project MAT2017-82182-R funded by the State Research Agency (SRA) of Spain and European Regional Development Fund (ERDF). Funding for open access charge: Universidad de Granada / CBUAHypothesis: Ice adhesion to rigid materials is reduced with low energy surfaces of high receding contact angles. However, their adhesion strength values are above the threshold value to be considered as icephobic materials. Surface deformability is a promising route to further reduce ice adhesion. Experiments: In this work, we prepared elastomer surfaces with a wide range of elastic moduli and hydrophobicity degree and we measured their ice adhesion strength. Moreover, we also explored the deicing performance of oil-infused elastomeric surfaces. The ice adhesion was characterized by two detachment modes: tensile and shear. Findings: The variety of elastomeric surfaces allowed us to simultaneously analyze the ice adhesion dependence with deformability and contact angle hysteresis. We found that the impact of these properties depends on the detachment mode, being deformability more important in shear mode and hydrophobicity more relevant in tensile mode. In addition, oil infusion further reduces ice adhesion due to the interfacial slippage. From an optimal balance between deformability and hydrophobicity, we were able to identify surfaces with super-low ice adhesion.MAT2017-82182-R State Research Agency (SRA)European Regional Development Fund (ERDF)Universidad de Granada / CBU

Instant messaging-based dialog system for device control in the Internet of things

La finalidad del proyecto im4Things es el desarrollo de una herramienta que proporcione una interfaz de comunicación entre humanos y dispositivos en la Internet de las cosas mediante diálogo en lenguaje natural escrito a través de servicios de mensajería instantánea. Esta comunicación puede ser de distintos tipos tales como el envío de órdenes, la consulta del estado e incluso se permite que sean los mismos dispositivos los encargados de alertar al usuario, si se ha producido un cambio del estado en los sensores de los dispositivos. Este proyecto está siendo desarrollado conjuntamente por la empresa Proasistech y el grupo TECNOMOD de la Universidad de Murcia y ha sido financiado por los fondos propios de la empresa Proasistech y con un contrato de I+D+i de asesoría tecnológica con el citado grupo de la Universidad de Murcia.The im4Things project aims to develop a communication interface to devices on the Internet of the Things (IoT) through intelligent dialogue based on written natural language over instant messaging services. This communication can be established in different ways such as order sending, status querying and even the devices themselves are responsible for alert users when a change has been produced in the devices sensors. This project is being developed by Proasistech company in cooperation with the TECNOMOD research group of the University of Murcia and it has been funded by equity capital of Proasistech company and by an R&D&i technology consulting contract with the aforementioned University of Murcia research group.Este trabajo ha sido financiado por la empresa Proasistech (http://www.proasistech.com/) a través de sus fondos propios

Oscillating Magnetic Drop: How to Grade Water-Repellent Surfaces

Evaluation of superhydrophobic (SH) surfaces based on contact angle measurements is challenging due to the high mobility of drops and the resolution limits of optical goniometry. For this reason, some alternatives to drop-shape methods have been proposed such as the damped-oscillatory motion of ferrofluid sessile drops produced by an external magnetic field. This approach provides information on surface friction (lateral/shear adhesion) from the kinetic energy dissipation of the drop. In this work, we used this method to compare the low adhesion of four commercial SH coatings (Neverwet, WX2100, Ultraever dry, Hydrobead) formed on glass substrates. As ferrofluid, we used a maghemite aqueous suspension (2% v/v) synthesized ad hoc. The rolling magnetic drop is used as a probe to explore shear solid–liquid adhesion. Additionally, drop energy dissipates due to velocity-dependent viscous stresses developed close to the solid–liquid interface. By fitting the damped harmonic oscillations, we estimated the decay time on each coating. The SH coatings were statistically different by using the mean damping time. The differences found between SH coatings could be ascribed to surface–drop adhesion (contact angle hysteresis and apparent contact area). By using this methodology, we were able to grade meaningfully the liquid-repelling properties of superhydrophobic surfaces.This research was financed by the State Research Agency (SRA) and European Regional Development Fund (ERDF) through the project MAT2017-82182-R. Fernando Vereda acknowledges financial support from MAT 2016-78778-R and PCIN-2015-051 projects (Spain)

Superhydrophobic Cerium-Based Coatings on Al-Mg Alloys and Aluminized Steel

Aluminum-magnesium (Al-Mg) alloy and aluminum-coated steel (aluminized steel) are typically used for the manufacturing of baking trays and molds. For these applications, these materials must be modified to develop release and hydrophobic properties. With this aim, the bare substrates are typically coated with low-surface energy materials such as fluoropolymers, elastomers, or sol-gel layers. In this work, some alternative strategies to prepare these functional surfaces are presented. We used three-step processes involving (i) micro-texturing, (ii) nano layer deposition through immersion and electrodeposition, and (iii) hydrophobization. The raw substrates were sanded or sandblasted at the micro scale, accordingly. Texturization at the nano scale was achieved with a cerium layer formed by electrodeposition or solution immersion. The cerium layers were hydrophobized with fatty acids. The wetting properties of the samples were studied with tilting-plate and bouncing drop methods. We measured the surface roughness of the samples by contact profiling and analyzed their surface morphology using a field emission scanning electron microscope (FESEM). The elemental chemical composition of the samples was analyzed by energy-dispersive X-ray spectroscopy (EDX). The wettability results indicated that the best performance for the Al-Mg substrates was reached by sandblasting and later immersion in a cerium nitrate solution. For aluminized steel substrates, the best results were obtained with both electrodeposition and immersion methods using a cerium chloride solution.The authors were supported by the University of Cordoba (Spain), which financed this work through the Own Research Plan 2019. This research was partially financed by the State Research Agency (SRA) and European Regional Development Fund (ERDF) through the project MAT2017-82182-R

Non-Stick Coatings in Aluminium Molds for the Production of Polyurethane Foam

The manufacturing of polyurethane foam is a process of great industrial importance in the automotive and furniture sector. The operation of demolding is the most delicate, since the foam sticks firmly to the walls of the mold onto which it has spread. In order to avoid the use of demolding agents, the proposal is to coat the inside of the molds with non-stick coatings. In this work, three types of different coatings were studied: fluoropolymers, ceramics, and elastomers. After carrying out different tests in the laboratory, two fluoropolymer coatings (PFA (perfluoroalkoxy) and PTFE (polytetrafluoroethylene)) were selected for a test at the industrial level and, after 1500 cycles of demolding, it was experimentally proven that the PFA coating is the most adequate for the use studied.This study was funded by the European Fund for Regional Development, the Ministry of Economy and Competitiveness of the Government of Spain and the Centre for Industrial Technological Development (CDTI) (nº ITC-2015237), as well as by Project for Excellence Andalusian Research Plan (P12-FQM-1443)

Water-Repellent Galvanized Steel Surfaces Obtained by Sintering of Zinc Nanopowder

Galvanized steel surfaces are widely used in industry as a solution to prevent corrosion of steel tools that operate in outdoor or corrosive and oxidative environments. These objects are coated with a zinc protective layer deposited by hot dip galvanization. Turning the surface of galvanized steel tools into superhydrophobic may lead to very useful functionalities, although it may be a difficult task, because the preservation of the thin zinc layer is a claim. We propose herein the use of a bottom-up approach based on sandblasting, followed by sintering of zinc nanoparticles on the galvanized steel substrate, which allowed us to produce a zinc-made hierarchical structure required for superhydrophobicity. These samples acquired a double-scale structure that led to superhydrophobicity when they were later hydrophobized with a thin fluoropolymer layer. We found that sandblasting might be useful but not mandatory, unlike the sintering process, which was essential to reach superhydrophobicity. We found that, under certain experimental conditions, the surfaces showed outstanding water-repellent properties. We observed that the sandblasting on galvanized steel caused more damage than the sintering process. Sintering of low-melting-point metal nanoparticles was revealed as a promising strategy to fabricate functional metallic surfaces.Ministerio de Ciencia e Innovación: PID2020-116082GB-I00.Program FEDER- Junta de Andaluciá : B-FQM-670-UGR20.European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 955612 (NanoPaInt

Non-Stick Coatings in Aluminium Molds for the Production of Polyurethane Foam

The manufacturing of polyurethane foam is a process of great industrial importance in the automotive and furniture sector. The operation of demolding is the most delicate, since the foam sticks firmly to the walls of the mold onto which it has spread. In order to avoid the use of demolding agents, the proposal is to coat the inside of the molds with non-stick coatings. In this work, three types of different coatings were studied: fluoropolymers, ceramics, and elastomers. After carrying out different tests in the laboratory, two fluoropolymer coatings (PFA (perfluoroalkoxy) and PTFE (polytetrafluoroethylene)) were selected for a test at the industrial level and, after 1500 cycles of demolding, it was experimentally proven that the PFA coating is the most adequate for the use studie