scholarly journals Enhanced Chemical and Electrochemical Stability of Polyaniline-Based Layer-by-Layer Films

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2992
Author(s):  
Putri Bintang Dea Firda ◽  
Yoga Trianzar Malik ◽  
Jun Kyun Oh ◽  
Evan K. Wujcik ◽  
Ju-Won Jeon
Keyword(s):  
Film Growth ◽  
Electrochemical Stability ◽  
Layer By Layer ◽  
Electrochromic Devices ◽  
Electroactive Material ◽  
Practical Applications ◽  
Lbl Assembly ◽  
Different Types ◽  
Lbl Films ◽  
Better Than

Polyaniline (PANI) has been widely used as an electroactive material in various applications including sensors, electrochromic devices, solar cells, electroluminescence, and electrochemical energy storage, owing to PANI’s unique redox properties. However, the chemical and electrochemical stability of PANI-based materials is not sufficiently high to maintain the performance of devices under many practical applications. Herein, we report a route to enhancing the chemical and electrochemical stability of PANI through layer-by-layer (LbL) assembly. PANI was assembled with different types of polyelectrolytes, and a comparative study between three different PANI-based layer-by-layer (LbL) films is presented here. Polyacids of different acidity and molecular structure, i.e., poly(acrylic acid) (PAA), polystyrene sulfonate (PSS), and tannic acid (TA), were used. The effect of polyacids’ acidity on film growth, conductivity, and chemical and electrochemical stability of PANI was investigated. The results showed that the film growth of the LbL system depended on the acidic strength of the polyacids. All LbL films exhibited improved chemical and electrochemical stability compared to PANI films. The doping level of PANI was strongly affected by the type of dopants, resulting in different chemical and electrochemical properties; the strongest polyacid (PSS) can provide the highest conductivity and chemical stability of conductive PANI. However, the electrochemical stability of PANI/PAA was found to be better than all the other films.

Construction of Antibacterial Surface Via Layer-by-Layer Method

2018 ◽  
Vol 24 (8) ◽  
pp. 926-935 ◽  
Author(s):  
Xianhua Zhang ◽  
Shaobo Ou-yang ◽  
Jiaolong Wang ◽  
Lan Liao ◽  
Runfa Wu ◽  
...  
Keyword(s):  
Antibacterial Agents ◽  
Deposition Process ◽  
Multilayer Thin Films ◽  
Layer By Layer ◽  
Lbl Assembly ◽  
Layer Method ◽  
Different Types ◽  
Antibacterial Surface ◽  
Materials Used ◽  
Antibacterial Surfaces

Construction of antibacterial surfaces or films is of great interest in various fields including biomedicine, food, agriculture and so on. So far, a number of antibacterial agents have been used to construct antibacterial surfaces. Layer-by-Layer (LbL) assembly is a simple and versatile deposition process for fabricating multilayer thin films with great advantages to control the architecture and composition of the films. In this review, we give a brief introduction of LbL, and different materials used to fabricate antibacterial surfaces with LbL assembly approach are described as well as their drawbacks. Much attention is also paid to the recent development of multifunctional and intelligent antibacterial surfaces. Moreover, the advantages and limitations of these different types of antibacterial materials are summarized and subsequently directions for future development are proposed.

scholarly journals Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Luiza A. Mercante ◽  
Vanessa P. Scagion ◽  
Adriana Pavinatto ◽  
Rafaela C. Sanfelice ◽  
Luiz H. C. Mattoso ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Chemical Sensors ◽  
Film Growth ◽  
Electronic Tongue ◽  
Principal Component ◽  
Inorganic Materials ◽  
Milk Analysis ◽  
Layer By Layer ◽  
Nanostructured Films ◽  
Lbl Films

The use of gold nanoparticles combined with other organic and inorganic materials for designing nanostructured films has demonstrated their versatility for various applications, including optoelectronic devices and chemical sensors. In this study, we reported the synthesis and characterization of gold nanoparticles stabilized with poly(allylamine hydrochloride) (Au@PAH NPs), as well as the capability of this material to form multilayer Layer-by-Layer (LbL) nanostructured films with metal tetrasulfonated phthalocyanines (MTsPc). Film growth was monitored by UV-Vis absorption spectroscopy, atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Once LbL films have been applied as active layers in chemical sensors, Au@PAH/MTsPc and PAH/MTsPc LbL films were used in an electronic tongue system for milk analysis regarding fat content. The capacitance data were treated using Principal Component Analysis (PCA), revealing the role played by the gold nanoparticles on the LbL films electrical properties, enabling this kind of system to be used for analyzing complex matrices such as milk without any prior pretreatment.

UV Resistant Poly(3,4-ethylenedioxythiophene) Thin Films: Layer-by-Layer Assembly with Absorbing Nanoparticles

2007 ◽  
Vol 1054 ◽  
Author(s):  
Thomas Dawidczyk ◽  
Jaime Grunlan
Keyword(s):  
Thin Films ◽  
Sheet Resistance ◽  
Film Growth ◽  
Environmental Stability ◽  
Layer By Layer ◽  
Bulk Resistivity ◽  
Flexible Display ◽  
Lbl Assembly ◽  
Order Of Magnitude ◽  
Magnitude Increase

ABSTRACTLayer-by-layer (LbL) assembly is used to create thin films by alternately exposing a substrate to positively- and negatively-charged molecules or particles in water. In recent years, LbL assemblies containing poly(3,4-ethylenedioxythiophene) (PEDOT) have been heavily studied, but little work has focused on improving the environmental stability of these thin films. Most intrinsically conductive polymers suffer from increasing resistance with exposure to ultraviolet light. In the present work, photolytic stability is improved by adding UV-absorbing nanoparticles to PEDOT assemblies. Films made by alternately depositing PEDOT-PSS and polyethylenimine (PEI) show an order of magnitude increase in sheet resistance after just 28 hours of exposure to 365 nm light. This degradation is cut in half by incorporating UV-absorbing nanoparticles, carbon black or titanium dioxide, into these assemblies. After more than 200 hours of exposure, films containing TiO2 nanoparticles have sheet resistance that is one fifth that of the unprotected PEDOT. In addition to adding UV-absorbing particles, the influence of doping and type of polycation on bulk resistivity and film growth were evaluated. These films are able to achieve bulk resistivity values below 1 Ohm cm with a thickness below 100 nm. When combined with transparency greater than 90%, these films may be useful for electrostatic dissipation layers or low conductivity electrodes in film or flexible display applications.

Resolution and measurement in the scanning electron microscope

1987 ◽  
Vol 45 ◽  
pp. 534-537 ◽  
Author(s):  
Michael T. Postek
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Engineering Design ◽  
Resolving Power ◽  
Practical Applications ◽  
Instrument Resolution ◽  
Accurate Definition ◽  
Definition Of ◽  
Scanning Electron ◽  
Better Than

The term ultimate resolution or resolving power is the very best performance that can be obtained from a scanning electron microscope (SEM) given the optimum instrumental conditions and sample. However, as it relates to SEM users, the conventional definitions of this figure are ambiguous. The numbers quoted for the resolution of an instrument are not only theoretically derived, but are also verified through the direct measurement of images on micrographs. However, the samples commonly used for this purpose are specifically optimized for the measurement of instrument resolution and are most often not typical of the sample used in practical applications.SEM RESOLUTION. Some instruments resolve better than others either due to engineering design or other reasons. There is no definitively accurate definition of how to quantify instrument resolution and its measurement in the SEM.

Design, Development and Comparison of Heuristic Driven Algorithms Based on the Crossed Domain Products’ Reviews for User’s Summarization

2020 ◽  
Vol 13 (5) ◽  
pp. 884-892
Author(s):  
Sartaj Ahmad ◽  
Ashutosh Gupta ◽  
Neeraj Kumar Gupta
Keyword(s):  
Decision Making ◽  
Online Shopping ◽  
Recent Time ◽  
Design Development ◽  
Different Types ◽  
Feature Based ◽  
Use Of Internet ◽  
Day By Day ◽  
Better Than

Background: In recent time, people love online shopping but before any shopping feedbacks or reviews always required. These feedbacks help customers in decision making for buying any product or availing any service. In the country like India this trend of online shopping is increasing very rapidly because awareness and the use of internet which is increasing day by day. As result numbers of customers and their feedbacks are also increasing. It is creating a problem that how to read all reviews manually. So there should be some computerized mechanism that provides customers a summary without spending time in reading feedbacks. Besides big number of reviews another problem is that reviews are not structured. Objective: In this paper, we try to design, implement and compare two algorithms with manual approach for the crossed domain Product’s reviews. Methods: Lexicon based model is used and different types of reviews are tested and analyzed to check the performance of these algorithms. Results: Algorithm based on opinions and feature based opinions are designed, implemented, applied and compared with the manual results and it is found that algorithm # 2 is performing better than algorithm # 1 and near to manual results. Conclusion: Algorithm # 2 is found better on the different product’s reviews and still to be applied on other product’s reviews to enhance its scope. Finally, it will be helpful to automate existing manual process.

Selective Hydrogen Bonding Controls Temperature Response of Layer-by-Layer Upper Critical Solution Temperature Micellar Assemblies

Soft Matter ◽  
2021 ◽  
Author(s):  
Aliaksei Aliakseyeu ◽  
Victoria Albright ◽  
Danielle Yarbrough ◽  
Samantha Hernandez ◽  
Qing Zhou ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Methacrylic Acid ◽  
Temperature Response ◽  
Solution Temperature ◽  
Layer By Layer ◽  
Critical Solution Temperature ◽  
Hydrogen Bonding Interactions ◽  
Upper Critical Solution Temperature ◽  
Lbl Films

This work establishes a correlation between the selectivity of hydrogen-bonding interactions and the functionality of micelle-containing layer-by-layer (LbL) assemblies. Specifically, we explore LbL films formed by assembly of poly(methacrylic acid)...

scholarly journals Thermally Stimulated Desorption Optical Fiber-Based Interrogation System: An Analysis of Graphene Oxide Layers’ Stability

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 70
Author(s):  
Maria Raposo ◽  
Carlota Xavier ◽  
Catarina Monteiro ◽  
Susana Silva ◽  
Orlando Frazão ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Layer By Layer ◽  
Film Stability ◽  
A Value ◽  
Device Reliability ◽  
Sensor Devices ◽  
Lbl Films ◽  
The Stability

Thin graphene oxide (GO) film layers are being widely used as sensing layers in different types of electrical and optical sensor devices. GO layers are particularly popular because of their tuned interface reflectivity. The stability of GO layers is fundamental for sensor device reliability, particularly in complex aqueous environments such as wastewater. In this work, the stability of GO layers in layer-by-layer (LbL) films of polyethyleneimine (PEI) and GO was investigated. The results led to the following conclusions: PEI/GO films grow linearly with the number of bilayers as long as the adsorption time is kept constant; the adsorption kinetics of a GO layer follow the behavior of the adsorption of polyelectrolytes; and the interaction associated with the growth of these films is of the ionic type since the desorption activation energy has a value of 119 ± 17 kJ/mol. Therefore, it is possible to conclude that PEI/GO films are suitable for application in optical fiber sensor devices; most importantly, an optical fiber-based interrogation setup can easily be adapted to investigate in situ desorption via a thermally stimulated process. In addition, it is possible to draw inferences about film stability in solution in a fast, reliable way when compared with the traditional ones.

scholarly journals Fighting Together against the Pandemic: Learning Multiple Models on Tomography Images for COVID-19 Diagnosis

AI ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 261-273
Author(s):  
Mario Manzo ◽  
Simone Pellino
Keyword(s):  
Network Architecture ◽  
State Of The Art ◽  
Ensemble Classification ◽  
Effective Vaccine ◽  
Rt Pcr ◽  
Neural Network Architecture ◽  
Experimental Phase ◽  
Different Types ◽  
Polymerase Chain ◽  
Better Than

COVID-19 has been a great challenge for humanity since the year 2020. The whole world has made a huge effort to find an effective vaccine in order to save those not yet infected. The alternative solution is early diagnosis, carried out through real-time polymerase chain reaction (RT-PCR) tests or thorax Computer Tomography (CT) scan images. Deep learning algorithms, specifically convolutional neural networks, represent a methodology for image analysis. They optimize the classification design task, which is essential for an automatic approach with different types of images, including medical. In this paper, we adopt a pretrained deep convolutional neural network architecture in order to diagnose COVID-19 disease from CT images. Our idea is inspired by what the whole of humanity is achieving, as the set of multiple contributions is better than any single one for the fight against the pandemic. First, we adapt, and subsequently retrain for our assumption, some neural architectures that have been adopted in other application domains. Secondly, we combine the knowledge extracted from images by the neural architectures in an ensemble classification context. Our experimental phase is performed on a CT image dataset, and the results obtained show the effectiveness of the proposed approach with respect to the state-of-the-art competitors.

scholarly journals Encapsulation of Phase Change Materials Using Layer-by-Layer Assembled Polyelectrolytes

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Qiangying Yi ◽  
Gleb B. Sukhorokov ◽  
Jin Ma ◽  
Xiaobo Yang ◽  
Zhongwei Gu
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Low Cost ◽  
Sodium Dodecyl ◽  
Layer By Layer ◽  
Latent Heat Storage ◽  
Good Thermal Stability ◽  
Lbl Assembly ◽  
Acid Sodium Salt ◽  
Assembly Technique

Phase change materials absorb the thermal energy when changing their phases (e.g., solid-to-liquid) at constant temperatures to achieve the latent heat storage. The major drawbacks such as limited thermal conductivity and leakage prevent the PCMs from wide application in desired areas. In this work, an environmentally friendly and low cost approach, layer-by-layer (LbL) assembly technique, was applied to build up ultrathin shells to encapsulate the PCMs and therefore to regulate their changes in volume when the phase change occurs. Generally, the oppositely charged strong polyelectrolytes Poly(diallyldimethylammonium chloride) (PDADMAC) and Poly(4-styrenesulfonic acid) sodium salt (PSS) were employed to fabricate multilayer shells on emulsified octadecane droplets using either bovine serum albumin (BSA) or sodium dodecyl sulfate (SDS) as surfactant. Specifically, using BSA as the surfactant, polyelectrolyte encapsulated octadecane spheres in size of ∼500 nm were obtained, with good shell integrity, high octadecane content (91.3% by mass), and good thermal stability after cycles of thermal treatments.

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