Nanostructured surfaces by supramolecular self-assembly of linear oligosilsesquioxanes with biocompatible side groups

Linear oligomeric silsesquioxanes with polar side moieties (e.g., carboxylic groups and derivatives of N-acetylcysteine, cysteine hydrochloride or glutathione) can form specific, self-assembled nanostructures when deposited on mica by dip coating. The mechanism of adsorption is based on molecule-to-substrate interactions between carboxylic groups and mica. Intermolecular cross-linking by hydrogen bonds was also observed due to the donor–acceptor character of the functional groups. The texture of supramolecular nanostructures formed by the studied materials on mica was analysed with atomic force microscopy and their specific surface energy was estimated by contact angle measurements. Significant differences in the surface roughness, thickness and the arrangement of macromolecules were noted depending on the kind of functional groups on the side chains. Specific changes in the morphology of the surface layer were observed when mica was primed with a monolayer of small organic compounds (e.g., N-acetylcysteine, citric acid, thioglycolic or acid). The adsorption of both silsesquioxane oligomers and organic primers was confirmed with attenuated total reflectance infrared spectroscopy. The observed physiochemical and textural variations in the adsorbed materials correlate with the differences in the chemical structure of the applied oligomers and primers.

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Nanostructural Lithography via Photo-Initiated Phase Transformation of Silica-Surfactant Assemblies

MRS Proceedings ◽

10.1557/proc-576-263 ◽

1999 ◽

Vol 576 ◽

Author(s):

D. A. Doshi ◽

N. HÜsing ◽

H. Fan ◽

A. J. Hurd ◽

C. J. Brinker

Keyword(s):

Self Assembly ◽

Uv Light ◽

Dip Coating ◽

Silica Film ◽

X Ray Diffraction ◽

Nanostructured Surfaces ◽

Force Microscopy ◽

Atomic Force ◽

Silica Source ◽

Inorganic Species

ABSTRACTCooperative self-assembly processes of inorganic species and amphiphilic molecules have experienced major advances over the past six years. The ability to design these materials with spatially controlled combinations of different mesophases or compositions, and therefore different properties, would greatly enhance their utility as nanofunctional surfaces.We present a simple lithographic procedure, which allows a deliberate control of structure and properties of a meso-ordered silica film through optical mediation. This nanostructural lithography process exploits the pH sensitivity of supra-molecular self-assembly which allows spatial control over mesophases in the thin film and a selective etching capability. Through the addition of a photoacid generator in the coating sol along with surfactant and silica source, dip coating results in continuous, ordered photosensitive films. Exposure to UV light through a mask produces local pH changes, inducing mesostructural phase transitions and an increase in the acidcatalyzed siloxane condensation rate in the exposed regions. Two surfactant systems, CTAB (CH3(CH2)15N+(CH3)3Br–) and Brij 56 (CH3(CH2)15(OCH2CH2)10OH) have been studied. X-ray diffraction, transmission and scanning electron microscopy, optical microscopy, ellipsometry, MAS-NMR and atomic force microscopy are used to characterize the patterned nanostructured surfaces.

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The Influence of the Operating Parameters of Titanium Electropolishing to Obtain Nanostructured Titanium Surfaces

Materials Science Forum ◽

10.4028/www.scientific.net/msf.727-728.1638 ◽

2012 ◽

Vol 727-728 ◽

pp. 1638-1642

Author(s):

Leonardo Marasca Antonini ◽

Rafael Gomes Mielczarski ◽

Caroline Pigatto ◽

Iduvirges Lourdes Müller ◽

Célia de Fraga Malfatti

Keyword(s):

Operating Parameters ◽

Nanostructured Titanium ◽

Nanostructured Surfaces ◽

Force Microscopy ◽

Angle Measurements ◽

Atomic Force ◽

Different Temperatures ◽

Titanium Surfaces

Titanium and Ti alloys have been widely used as biomaterial due to their mechanical properties and high in vitro and in vivo cytocompatibility. Studies have showed that the acceleration of the osseointegration process is associated to the modification of the surface morphology. The aim of this work is to study the influence of the operating parameters of titanium electropolishing to obtain nanostructured titanium surfaces. The titanium electropolishing was carried out with different temperatures (7°C, 18°C and 25°C), current density of 0.19 A/cm2 and electropolishing time of 8 minutes. After the electropolishing process the titanium samples were characterized by Atomic Force Microscopy, profilometry (mechanical profilometer) and contact angle measurements. Preliminary results showed that the Ti nanostructured surfaces formation, strongly depends on the control of operating parameters.

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Functionalized Waveguides for Biological Assays

MRS Proceedings ◽

10.1557/proc-0950-d04-38 ◽

2006 ◽

Vol 950 ◽

Author(s):

Aaron S. Anderson ◽

Andrew M. Dattelbaum ◽

Gabriel A. Montaño ◽

Jurgen G. Schmidt ◽

Jennifer S. Martinez ◽

...

Keyword(s):

Self Assembly ◽

Protective Antigen ◽

Specific Binding ◽

Biological Assays ◽

Force Microscopy ◽

Sensing Applications ◽

Angle Measurements ◽

Atomic Force ◽

Functionalized Surfaces ◽

Contact Angle Measurements

ABSTRACTWe report here a procedure for the functioalization of SiO2-coated, SiONx waveguides for biological assays. Surface functionalization occurs by self-assembly of an amine-terminated silane monolayer on the waveguide, followed by partial chemical modification with functionalized polyethylene glycol (PEG) groups. Functionalized surfaces were characterized by atomic force microscopy and contact angle measurements. When combined with a BSA blocking step, these functional PEG surfaces significantly reduced non-specific binding and allowed for specific binding to occur. An antibody sandwich assay for detection of Bacillus anthracis protective antigen was used to validate these surfaces for sensing applications.

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On the Properties of Yttria-Stabilized Zirconia Thin Films Prepared by Sol-Gel Method

Materials Science ◽

10.5755/j01.ms.17.2.491 ◽

1970 ◽

Vol 17 (2) ◽

pp. 191-196

Author(s):

Artūras ŽALGA ◽

Brigita ABAKEVIČIENĖ ◽

Aleksej ŽARKOV ◽

Aldona BEGANSKIENĖ ◽

Aivaras KAREIVA ◽

...

Keyword(s):

Thin Films ◽

Sol Gel ◽

Xrd Analysis ◽

Dip Coating ◽

X Ray Diffraction ◽

Force Microscopy ◽

Angle Measurements ◽

Atomic Force ◽

Contact Angle Measurements ◽

Dip Coating Technique

The synthesis of nanostructured films of 20 mol% Y2O3 stabilized ZrO2 on corundum (Al2O3) substrates was performed from different sols using dip-coating technique. All obtained samples were repeatedly annealed at 800 °C temperature after each dipping procedure and fully characterized by X-ray diffraction (XRD) analysis. XRD data exhibited that at 800 °C temperature nano-sized Y0.2Zr0.8O2 thin films with cubic (Fm-3m) crystal structure have been formed. The morphological features of obtained coatings were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface tension and hydrophility of the synthesized films were determined by contact angle measurements (CAM).http://dx.doi.org/10.5755/j01.ms.17.2.491

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The Effects of the Self-Assembly Time on the Preparation of Lanthanum-Based Thin Films on Sulfonated 3-Mercaptopropyl Trimethoxysilane

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.164.284 ◽

2012 ◽

Vol 164 ◽

pp. 284-288

Author(s):

Tao Bai ◽

Xian Hua Cheng

Keyword(s):

Thin Films ◽

Photoelectron Spectroscopy ◽

Self Assembly ◽

Self Assembled Monolayer ◽

X Ray ◽

Assembly Time ◽

Force Microscopy ◽

Angle Measurements ◽

Atomic Force ◽

Contact Angle Measurements

Lanthanum-based thin films are deposited on the oxidized 3-mercaptopropyl trimethoxysilane self-assembled monolayer (MPTS-SAM) based on the chemisorption of the sulfonic group. The surface energy, chemical composition, phase transformation and surface morphology of the films are analyzed by using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The experimental results indicate that the lanthanum-based thin films are absorbed on oxidized MPTS-SAM and lanthanum element with different oxidation states exists in the thin films deposited on the surface of self-assembly monolayers. The content of lanthanum on the oxidized MPTS-SAM increases with the extension of the assembly time and the rare earth reached saturation when the time was 6h.

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Wrinkling Poly(trimethylene 2,5-Furanoate) Free-standing Films: Nanostructure Formation and Physical Properties

10.26434/chemrxiv.11867205.v1 ◽

2020 ◽

Author(s):

Michelina Soccio ◽

Nadia Lotti ◽

Andrea Munari ◽

Esther Rebollar ◽

Daniel E Martínez-Tong

Keyword(s):

Irradiation Time ◽

Polymer Surface ◽

Laser Source ◽

Free Standing ◽

Force Microscopy ◽

Nanostructure Formation ◽

Physicochemical Changes ◽

Angle Measurements ◽

Atomic Force ◽

Contact Angle Measurements

<p>Nanostructured wrinkles were developed on fully bio-based poly(trimethylene furanoate) (PTF) films by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We investigated the effect of irradiation time on wrinkle formation using an UV pulsed laser source, at a fluence of 8 mJ/cm2. It was found that the pulse range between 600 and 4800 pulses allowed formation of periodic nanometric ripples. The nanostructured surface was studied using a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic physicochemical properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethyleneterephthalate), PET, and poly(trimethyleneterephthalate), PTT. The surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by nanomechanical force spectroscopy measurements. In particular, an increased Young’s modulus and higher stiffness for the nanostructured sample were measured. <br></p>

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Clathrin-Inspired Coating and Stabilization of Liposomes by DNA Self-Assembly

10.26434/chemrxiv.8859017.v1 ◽

2019 ◽

Author(s):

Kevin N. Baumann ◽

Luca Piantanida ◽

Javier García-Nafría ◽

Diana Sobota ◽

Kislon Voïtchovsky ◽

...

Keyword(s):

Self Assembly ◽

Mechanical Stability ◽

Lipid Vesicles ◽

The Self ◽

Force Microscopy ◽

Atomic Force ◽

Cryo Electron Microscopy ◽

Further Development ◽

Liposome Surface ◽

Dna Coating

The self-assembly of the protein clathrin on biological membranes facilitates essential processes of endocytosis in biological systems and has provided a source of inspiration for materials design by the highly ordered structural appearance. By mimicking the architecture of clathrin self-assemblies to coat liposomes with biomaterials, new classes of hybrid carriers can be derived. Here we present a method for fabricating DNA-coated liposomes by hydrophobically anchoring and subsequently growing a DNA network on the liposome surface which structurally mimics clathrin assemblies. Dynamic light scattering (DLS), ζ-potential and cryo-electron microscopy (cryo-EM) measurements independently demonstrate successful DNA coating. Nanomechanical measurements conducted with atomic force microscopy (AFM) show that the DNA coating enhances the mechanical stability of the liposomes relative to uncoated ones. Furthermore, we provide the possibility to reverse the coating process by triggering the disassembly of the DNA coating through a toehold-mediated displacement reaction. Our results describe a straightforward, versatile, and reversible approach for coating and stabilizing lipid vesicles by an interlaced DNA network. This method has potential for further development towards the ordered arrangement of tailored functionalities on the surfaces of liposomes and for applications as hybrid nanocarrier.

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Effects of Hydroxyl and Carboxyl Functional Groups on Calcite Surface Wettability Using Atomic Force Microscopy and Density Functional Theory

ACS Earth and Space Chemistry ◽

10.1021/acsearthspacechem.1c00240 ◽

2021 ◽

Author(s):

Sooyeon Kim ◽

Maria C. Marcano ◽

Udo Becker

Keyword(s):

Density Functional Theory ◽

Atomic Force Microscopy ◽

Functional Groups ◽

Density Functional ◽

Surface Wettability ◽

Functional Theory ◽

Force Microscopy ◽

Atomic Force

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Micro/Nano-Tribological Behavior of Octadecyltrichlorosilane on Silicon as a Coating for MEMS

World Tribology Congress III, Volume 2 ◽

10.1115/wtc2005-63491 ◽

2005 ◽

Author(s):

J. Barriga ◽

B. Ferna´ndez ◽

E. Abad ◽

B. Coto

Keyword(s):

Liquid Phase ◽

Vapour Phase ◽

Stick Slip ◽

Force Microscopy ◽

Angle Measurements ◽

Atomic Force ◽

Contact Angle Measurements ◽

Assembled Monolayers ◽

The Coefficient Of Friction ◽

Semicontact Mode

Despite progresses achieved in the technology of MEMS, the tribological problem continues being an unresolved matter. Wear and stick-slip phenomena are many times the origin of failure of these devices. The application of self-assembled monolayers (SAMs) in liquid phase seems to be a solution to this problems. SAMs of octadecyltrichlorosilane (CH3(CH2)17SiCl3, OTS) were attached to Si(100) oxidized in liquid phase. Contact angle measurements were used for characterizing the grade of hydrophobicity. The topography of the coating was obtained with an Atomic Force Microscopy (AFM) in semicontact mode. The images showed the presence of particles related to the polymerization of the precursor molecule during the formation process of the SAMs. Creating the film of lubricant in vapour phase would avoid this undesirable effect. Tribological tests were carried out with a microtribometer in linear reciprocating movement with a ball of 2 mm of diameter (100Cr6 and Si3N4) and load of some milinewtons. Results were compared with those obtained for silicon oxidized without any coating. The coefficient of friction (COF) and wear (substrate and ball) were studied under different test conditions.

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