Molecular Self-Assembly of Fe3O4/Polyimide Nanocomposite Films (I)

1997 ◽  
Vol 475 ◽  
Author(s):  
Yanjing Liu ◽  
Anbo Wang ◽  
Richard O. Claus ◽  
Eric Jiang
Keyword(s):  
Aqueous Solution ◽  
Self Assembly ◽  
Single Crystal Silicon ◽  
Magnetic Films ◽  
Nanocomposite Films ◽  
Layer By Layer ◽  
Crystal Silicon ◽  
Vis Spectroscopy ◽  
Polyimide Nanocomposite ◽  
Polyimide Precursor

ABSTRACTLayer-by-layer molecular self-assembly of nanosized magnetite (Fe3O4) particles and polyimide precursor molecules into multilayer ultrathin films has been accomplished on single crystal silicon and quartz substrates. This process involves the alternate dipping of a substrate into an aqueous solution of cationic polymer which coats on nanoscale Fe3O4 particles as a stabilizer followed by dipping into an aqueous solution of anionie polyimide precursor (polyamic acid salt, PAATEA). The growth process and the structure have been characterized using UV-vis spectroscopy, FT-IR, and scanning electron microscopy. The results demonstrate that well-ordered uniform monolayer and multilayer magnetic films have been formed on silicon and silica surfaces.

Giant Magnetoresistance of Electrostatic Self-Assembled Fe3O4 Nanocluster and Polymer Thin-Films

1999 ◽  
Vol 577 ◽  
Author(s):  
Yanjing Liu ◽  
Richard O. Claus ◽  
Fajian Zhang
Keyword(s):  
Aqueous Solution ◽  
Self Assembly ◽  
Giant Magnetoresistance ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Angle Measurements ◽  
Vis Spectroscopy ◽  
Contact Angle Measurements ◽  
Assembly Technique ◽  
Quartz Substrates

ABSTRACTGiant magnetoresistance (GMR) as large as 25% at 25°C has been observed for multilayer ultrathin films of iron oxide (Fe3O4) nanoclusters and polyimide molecules alternately adsorbed onto single crystal silicon and quartz substrates using a novel self-assembly technique. This process involves the alternate dipping of a substrate into an aqueous solution of anionic polyimide precursor (polyamic salt, PAA) followed by dipping it into an aqueous solution of cationic polydiallyldimethylammonium chloride (PDDA)-coated Fe3O4, nanoparticles. The regular formation of alternating monolayers is verified by UV-vis spectroscopy and contact angle measurements. Vibrating sample magnetometry indicates the formation of ultrasoft films.

A New Route to Prepare Hard and Anti-Scratching Coatings at Room Temperature

1999 ◽  
Vol 576 ◽  
Author(s):  
Yanjing Liu ◽  
Richard O. Claus ◽  
Aprillya Rosidian ◽  
Tingying Zeng
Keyword(s):  
Thin Films ◽  
Self Assembly ◽  
Room Temperature ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Linear Behavior ◽  
Vis Spectroscopy ◽  
Novel Method ◽  
Quartz Substrates ◽  
Cationic Polyelectrolytes

ABSTRACTNanocomposites of transparent, multilayer structures of different thin-films have been fabricated on single crystal silicon and quartz substrates by the new deposition technique called electrostatic self-assembly (ESA) method. The method is based on the alternating adsorption of anionic and cationic polyelectrolytes in the aqueous forms. The films were then characterized by UV/Vis spectroscopy, ellipsometry, and nano-indenter. A linear behavior of both optical absorption and film thickness as the number of bilayers increases was observed, which indicated the formation of homogeneous and uniform thin-films on both substrates. The study also observed that the films prepared by this novel method have some improved mechanical properties.

Layer-by-Layer Self-Assembly: Toward Magnetic Films with Tunable Anisotropy

2015 ◽  
Vol 119 (23) ◽  
pp. 13215-13223 ◽  
Author(s):  
Wenying Shi ◽  
Ruizheng Liang ◽  
Simin Xu ◽  
Yanming Wang ◽  
Chaojie Luo ◽  
...  
Keyword(s):  
Self Assembly ◽  
Magnetic Films ◽  
Layer By Layer

Facile fabrication of flexible Si-based nanocomposite films as high-rate anodes by layer-by-layer self-assembly

2019 ◽  
Vol 476 ◽  
pp. 501-512 ◽  
Author(s):  
Lehao Liu ◽  
Meicheng Li ◽  
Lihua Chu ◽  
Bing Jiang ◽  
Ruoxu Lin
Keyword(s):  
Self Assembly ◽  
High Rate ◽  
Nanocomposite Films ◽  
Layer By Layer ◽  
Facile Fabrication

Preparation of CPC-Fe3O4-MMT/PEG Magnetic Films via Layer-by-Layer Assembly under the Assistance of Magnetic Field

2016 ◽  
Vol 852 ◽  
pp. 1034-1038
Author(s):  
Li Nan Xu ◽  
Shu Chen Tu ◽  
Feng Zhu Lv ◽  
Qi An ◽  
Yi He Zhang
Keyword(s):  
Magnetic Field ◽  
Self Assembly ◽  
Present Method ◽  
Multilayer Film ◽  
Composite Films ◽  
Deposition Efficiency ◽  
Magnetic Films ◽  
Layer By Layer ◽  
Film Fabrication ◽  
Layer Assembly

Polyethylene glycol (PEG), which was not a traditional building block of layer by layer (LBL) self-assembly, was used to fabricate multilayer films by the combination of LBL and magnetic field induction. The UV-abs absorbance of the composite films increases linearly with the number of bilayers, indicating uniform fabrication of each layer. By this method, the multilayers can consist of up to 15 bilayers. The applied magnetic field not only enhances the compactness of the CPC-Fe3O4-MMT, but also improves the deposition efficiency of the films. The present method can be an effective method for multilayer film fabrication from non polyelectrolyte.

scholarly journals On the Aqueous Solution Behavior of C-Substituted 3,1,2-Ruthenadicarbadodecaboranes

Inorganics ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 91 ◽  
Author(s):  
Marta Gozzi ◽  
Benedikt Schwarze ◽  
Peter Coburger ◽  
Evamarie Hey-Hawkins
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Self Assembly ◽  
Self Assembling ◽  
Vis Spectroscopy ◽  
Assembly Behavior ◽  
Biological Performance ◽  
Type 3

3,1,2-Ruthenadicarbadodecaborane complexes bearing the [C2B9H11]2− (dicarbollide) ligand are robust scaffolds, with exceptional thermal and chemical stability. Our previous work has shown that these complexes possess promising anti-tumor activities in vitro, and tend to form aggregates (or self-assemblies) in aqueous solutions. Here, we report on the synthesis and characterization of four ruthenium(II) complexes of the type [3-(η6-arene)-1,2-R2-3,1,2-RuC2B9H9], bearing either non-polar (R = Me (2–4)) or polar (R = CO2Me (7)) substituents at the cluster carbon atoms. The behavior in aqueous solution of complexes 2, 7 and the parent unsubstituted [3-(η6-p-cymene)-3,1,2-RuC2B9H11] (8) was investigated via UV-Vis spectroscopy, mass spectrometry and nanoparticle tracking analysis (NTA). All complexes showed spontaneous formation of self-assemblies (108–109 particles mL−1), at low micromolar concentration, with high polydispersity. For perspective applications in medicine, there is thus a strong need for further characterization of the spontaneous self-assembly behavior in aqueous solutions for the class of neutral metallacarboranes, with the ultimate scope of finding the optimal conditions for exploiting this self-assembling behavior for improved biological performance.

Surface Modification Energized by FIB: The Influence of Etch Rates & Aspect Ratio on Ripple Wavelengths

2006 ◽  
Vol 960 ◽  
Author(s):  
Warren MoberlyChan
Keyword(s):  
Aspect Ratio ◽  
Self Assembly ◽  
Focused Ion Beam ◽  
Process Development ◽  
Ion Beam ◽  
Natural Diamond ◽  
Single Crystal Silicon ◽  
Nanometer Scale ◽  
Crystal Silicon ◽  
Etch Rates

ABSTRACTIon beams have been used to modify surface topography, producing nanometer-scale modulations (and even subnanometer ripples in this work) that have potential uses ranging from designing self-assembly structures, to controlling stiction of micromachined surfaces, to providing imprint templates for patterned media. Modern computer-controlled Focused Ion Beam tools enable alternating submicron patterned zones of such ion-eroded surfaces, as well as dramatically increasing the rate of ion beam processing. The DualBeam FIB/SEM also expedites process development while minimizing the use of materials that may be precious (Diamond) and/or produce hazardous byproducts (Beryllium). A FIB engineer can prototype a 3-by-3-by-3 matrix of variables in tens of minutes and consume as little as zeptoliters of material; whereas traditional ion beam processing would require tens of days and tens of precious wafers. Saturation wavelengths have been reported for ripples on materials such as single crystal silicon or diamond (∼200nm); however this work achieves wavelengths >400nm on natural diamond. Conversely, Be can provide a stable and ordered 2-dimensional array of <40nm periodicity. Also ripples <0.4nm are fabricated on carbon-base surfaces, and these quantized picostructures are measured by HR-TEM and electron diffraction. Rippling is a function of material, ion beam, and angle; but is also controlled by chemical environment, redeposition, and aspect ratio. Ideally a material has a constant yield (atoms sputtered off per incident ion); however, pragmatic FIB processes, coupled with the direct metrological feedback in a DualBeam tool, reveal etch rates do not remain constant for nanometer-scale processing. Control of rippling requires controlled metrology, and robust software tools are developed to enhance metrology. In situ monitoring of the influence of aspect ratio and redeposition at the micron scale correlates to the rippling fundamentals that occur at the nanometer scale and are controlled by the boundary conditions of FIB processing.

Preparation and Characterization of Nano-Films Materials

2011 ◽  
Vol 492 ◽  
pp. 160-163
Author(s):  
Cai Xia Li ◽  
Qing Lv ◽  
Jie Song ◽  
Dan Yu Jiang ◽  
Qiang Li
Keyword(s):  
Self Assembly ◽  
Chemical Properties ◽  
Layered Compounds ◽  
Insertion Reaction ◽  
Layer By Layer ◽  
Vis Spectroscopy ◽  
Assembly Technique ◽  
Assembly Technology ◽  
Physical And Chemical

Nano-sheets are two-dimensional sheet materials exfoliated from the inorganic layered compounds by various physical and chemical methods. Their unique characteristics insertion reaction and excellent physical and chemical properties have attracted more and more researchers' widespread interests. Selecting quartz glass as the substrate, using layer by layer self-assembly technology, different nano-films materials are prepared. UV/Vis spectroscopy confirmed nano-films materials have been successfully assembled using LBL self-assembly technique. Raman spectrum are mainly used to analyze and characterize the structure of nano-films materials.

Preparation of Poly(diallydimethyl ammonium chloride) (PDDA)/Au Nanocomposite Film by In Situ Electrochemical Reduction and its Electrocatalytic Properties

2010 ◽  
Vol 123-125 ◽  
pp. 189-192
Author(s):  
Hong Wei Shi ◽  
Li Zhang ◽  
Cong Wang ◽  
Ke Ying Zhang
Keyword(s):  
Electrochemical Reduction ◽  
Ammonium Chloride ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Layer By Layer ◽  
X Ray ◽  
Assembly Technique

Nanocomposite films containing Au nanoparticles were fabricated by alternating adsorption of poly(diallydimethyl ammonium chloride) (PDDA) and HAuCl4 using layer-by-layer self-assembly technique and subsequent in situ electrochemical reduction of the AuCl4- ions. The composition and properties of the composite films were characterized by ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV).The UV-vis characteristic absorbances of PDDA and Au increase almost linearly with the number of bilayers, which suggests a progressive deposition with almost an equal amount of the PDDA and Au in each cycle. X-ray photoelectron spectroscopy further confirms the presence of the main components (such as PDDA and Au) of the nanocomposite films. Furthermore, the nanocomposite films also exhibit good electrocatalytic activity for the oxidation of ascorbic acid (AA), which may be used in electrochemical biosensors.

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