Nonlinear Layer-by-Layer Films: Effects of Chain Diffusivity on Film Structure and Swelling

2017 ◽  
Vol 50 (16) ◽  
pp. 6192-6201 ◽  
Author(s):  
Victor Selin ◽  
John F. Ankner ◽  
Svetlana A. Sukhishvili
Keyword(s):  
Film Structure ◽  
Layer By Layer ◽  
Nonlinear Layer

scholarly journals Chitosan–Azide Nanoparticle Coating as a Degradation Barrier in Multilayered Polyelectrolyte Drug Delivery Systems

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 573 ◽  
Author(s):  
Steffen Sydow ◽  
Armin Aniol ◽  
Christoph Hadler ◽  
Henning Menzel
Keyword(s):  
Drug Delivery Systems ◽  
Uv Light ◽  
Film Structure ◽  
Layer By Layer ◽  
Multilayer Systems ◽  
Ionotropic Gelation ◽  
Physiological Conditions ◽  
Degree Of Acetylation ◽  
Implant Coating ◽  
The Stability

Therapeutics, proteins or drugs, can be encapsulated into multilayer systems prepared from chitosan (CS)/tripolyphosphat (TPP) nanogels and polyanions. Such multilayers can be built-up by Layer-by-Layer (LbL) deposition. For use as drug-releasing implant coating, these multilayers must meet high requirements in terms of stability. Therefore, photochemically crosslinkable chitosan arylazide (CS–Az) was synthesized and nanoparticles were generated by ionotropic gelation with TPP. The particles were characterized with regard to particle size and stability and were used to form the top-layer in multilayer films consisting of CS–TPP and three different polysaccharides as polyanions, namely alginate, chondroitin sulfate or hyaluronic acid, respectively. Subsequently, photo-crosslinking was performed by irradiation with UV light. The stability of these films was investigated under physiological conditions and the influence of the blocking layer on layer thickness was investigated by ellipsometry. Furthermore, the polyanion and the degree of acetylation (DA) of chitosan were identified as additional parameters that influence the film structure and stability. Multilayer systems blocked with the photo-crosslinked chitosan arylazide showed enhanced stability against degradation.

Layer-by-layer assembly of polymeric complexes: Effect of storing time on the complexes and film structure

2018 ◽  
Vol 59 (S1) ◽  
pp. E394-E402 ◽  
Author(s):  
Xiaoling Chen ◽  
Qiaojing Guo ◽  
Miaomiao He ◽  
Yongmei Liu ◽  
Yansheng Zhao
Keyword(s):  
Film Structure ◽  
Layer By Layer ◽  
Layer By Layer Assembly ◽  
Polymeric Complexes ◽  
Layer Assembly

A Photoluminescence Study of Film Structure in CdTe Nanoparticle Thin Films

2008 ◽  
Vol 8 (5) ◽  
pp. 2578-2581 ◽  
Author(s):  
H. C. Gardner ◽  
D. E. Gallardo ◽  
S. Dunn ◽  
N. Gaponik ◽  
A. Eychmüller
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Energy Transfer ◽  
Film Structure ◽  
Particle Energy ◽  
Energy Change ◽  
Layer By Layer ◽  
Cdte Nanoparticles ◽  
Layer Deposition ◽  
Stage Process

The layer-by-layer deposition of thin films of CdTe nanoparticles and three different polyelectrolytes has been investigated. Photoluminescence spectra were used to monitor the energy transfer properties within the films. As the number of bilayers in a thin film was increased a decrease in the energy of the light emitted was observed. The wavelength change is a two-stage process. Deposition of the first one to two bi-layers of a thin film produced a sharp energy change (626 nm to 637 nm with the addition of a single bi-layer) whereas deposition of subsequent bi-layers produced a more gradual energy change (642 nm–646 nm with the addition of 5 bi-layers). A space-filling mechanism is suggested to account for these changes; smaller nanoparticles penetrate the earlier levels of a thin film and increase the inter-particle energy transfer opportunities within the layers.

Ultrathin Films of Oriented Bacteriorhodopsin: Nanostructured Films for Investigating the Primary Photoevent in Vision Processes

2001 ◽  
Vol 679 ◽  
Author(s):  
Rigoberto C. Advincula ◽  
Mi-kyoung Park
Keyword(s):  
Ultrathin Films ◽  
Supramolecular Assembly ◽  
Solid Substrate ◽  
Film Structure ◽  
Glass Electrode ◽  
Layer By Layer ◽  
Ph Change ◽  
Force Microscopy ◽  
Atomic Force ◽  
Substrate Surfaces

ABSTRACTIn this work, a protocol for investigating Bacteriorhodopsin (BR) biomimetic systems as ultrathin films is presented. BR is one of the most well studied proteins important for investigating the primary photo-event in vision processes. The use of macromolecular assembly approaches for deposition onto solid support substrates, e.g. SiOx, gold- or ITO-coated glass (electrode) provide advantages in that surface sensitive measurements can be used to correlate photocurrent generation, photoelectric response, pH change, chromophore behavior, etc. with protein orientation at interfaces. Membrane and protein morphology were correlated to measurements using surface sensitive techniques, such as atomic force microscopy (AFM), ellipsometry, quartz crystal microbalance (QCM), etc. on solid-substrate systems. These studies can lead to applications in optobioelectronic devices (biosensors) including patterning in transducer array configurations, where the film structure is important. Hybrid films are possible with supramolecular assembly approaches, e.g. adsorption of membrane with lipidbilayers. We report our initial results on highly ordered and oriented BR protein arrays of controlled thickness, layer order, and orientation. This was done primarily using the alternate polyelectrolyte deposition (APD) or layer-by-layer (LbL) approach to functionalize substrate surfaces.

scholarly journals Tailoring the nanoscale morphology of HKUST-1 thin films via codeposition and seeded growth

2017 ◽  
Vol 8 ◽  
pp. 2307-2314 ◽  
Author(s):  
Landon J Brower ◽  
Lauren K Gentry ◽  
Amanda L Napier ◽  
Mary E Anderson
Keyword(s):  
Film Thickness ◽  
Film Formation ◽  
Full Range ◽  
Deposition Process ◽  
Film Structure ◽  
Layer By Layer ◽  
Seeded Growth ◽  
Seed Crystals ◽  
Control Film ◽  
Surface Morphologies

Integration of surface-anchored metal-organic frameworks (surMOFs) within hierarchical architectures is necessary for potential sensing, electronic, optical, or separation applications. It is important to understand the fundamentals of film formation for these surMOFs in order to develop strategies for their incorporation with nanoscale control over lateral and vertical dimensions. This research identified processing parameters to control the film morphology for surMOFs of HKUST-1 fabricated by codeposition and seeded deposition. Time and temperature were investigated to observe film formation, to control film thickness, and to tune morphology. Film thickness was investigated by ellipsometry, while film structure and film roughness were characterized by atomic force microscopy. Films formed via codeposition resulted in nanocrystallites anchored to the gold substrate. A dynamic process at the interface was observed with a low density of large particulates (above 100 nm) initially forming on the substrate; and over time these particulates were slowly replaced by the prevalence of smaller crystallites (ca. 10 nm) covering the substrate at a high density. Elevated temperature was found to expedite the growth process to obtain the full range of surface morphologies with reasonable processing times. Seed crystals formed by the codeposition method were stable and nucleated growth throughout a subsequent layer-by-layer deposition process. These seed crystals templated the final film structure and tailor the features in lateral and vertical directions. Using codeposition and seeded growth, different surface morphologies with controllable nanoscale dimensions can be designed and fabricated for integration of MOF systems directly into device architectures and sensor platforms.

scholarly journals Characterization of Strong and Crystalline Polyvinyl Alcohol/Montmorillonite Films Prepared by Layer-by-Layer Deposition Method

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
S. Gaidukov ◽  
I. Danilenko ◽  
G. Gaidukova
Keyword(s):  
Polyvinyl Alcohol ◽  
Thermal Studies ◽  
High Strength ◽  
Film Structure ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Layer Deposition

The preparation of a high-strength and highly crystalline nanocomposite with a layered structure by the use of layer-by-layer deposition (LbL) method from polyvinyl alcohol (PVOH) and montmorillonite (MMT) platelets is reported. The crystallinity and interactions between the components were studied by the use of Fourier transform infrared spectroscopy (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The nanocomposite film structure was investigated by the use of scanning electron microscope (SEM) and atomic force microscopy (AFM). The stiffness of the LbL PVOH/MMT film was significantly higher compared to pure PVOH and conventional PVOH/MMT nanocomposite. The structural and thermal studies on thin PVOH/MMT films indicated the enhanced crystallinity of the polymer.

scholarly journals Design of MoS2/graphene heterostructure thin film sensors for high performance NO2 gas sensor applications

2021 ◽  
Vol 2070 (1) ◽  
pp. 012131
Author(s):  
R Sakthivel ◽  
A Geetha ◽  
B A Anandh ◽  
V Jagadeesan ◽  
A Shankar Ganesh ◽  
...  
Keyword(s):  
Thin Film ◽  
High Performance ◽  
Gas Sensing ◽  
Spray Pyrolysis Technique ◽  
Fast Response ◽  
Film Structure ◽  
Layer By Layer ◽  
Large Area ◽  
Film Sensor ◽  
Bet Analysis

Abstract In this paper, we fabricate a large-area chemiresitive type MoS2/graphene films sensor is grown by spray pyrolysis technique. The prepared sensor films were characterization by XRD, SEM, TEM Raman and BET analysis. The synergistic effect between MoS2 and graphene through the CVD method produces such a hierarchical layer-by-layer assembly of the thin film structure. MoS2/graphene hybrid films not only show enhanced NO2 sensitivity compared to NO2 sensitivity alone. Graphene or MoS2 films, but they also exhibit characteristics of rapid response and strong reproducibility. Selectiveness and stability findings demonstrate the outstanding sensing properties of the MoS2 thin film sensor. The MoS2/G showed higher sensitivity (81%) towards NO2 gas at the concentration of 1000 ppm followed by graphene (22 %) and MoS2 (45 %) based sensors in sequence. The MoS2/G sensor also exhibits fast response (12 s) and recovery time (17 s) than other sensor samples. The concept of operation and sensing mechanism behind their impressive results has also been studied in depth. The effect of humidity on the performance of gas sensing was also discussed in the point of practical device applications.

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

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