Electric Field-Assisted Additive Manufacturing Polyaniline Based Composites for Thermoelectric Energy Conversion

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Bruce Y. Decker ◽  
Yong X. Gan
Keyword(s):  
Electron Microscopy ◽  
Additive Manufacturing ◽  
Composite Materials ◽  
Electric Field ◽  
Electrical Resistance ◽  
Alloy Nanoparticles ◽  
Electric Force ◽  
Thermoelectric Energy ◽  
Uniform Dispersion ◽  
Pani Matrix

Polyaniline (PANi) based composites were made by electric force assisted nanocasting. The PANi matrix was mixed with thermoelectric Bi–Te alloy nanoparticles. The uniform dispersion of the nanoparticles in the polymer was achieved via electric field assisted casting. The nanoparticles can enhance the thermoelectricity, specifically increase the Seebeck coefficient. Structure analysis and Seebeck effect experiments were performed. The microstructure of the composite materials was studied by the use of electron microscopy. The preliminary results show that the nanocomposites are n-type with an average Seebeck value of 30 μV/K. The electrical resistance of the composites is about 35 MΩ.

scholarly journals Nanofibrous piezoelectric structures for composite materials to be used in electrical and electronic components

2019 ◽  
pp. 1-5 ◽  
Author(s):  
D Fabiani ◽  
F Grolli ◽  
G Selleri ◽  
M Speranza ◽  
T M Brugo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Composite Materials ◽  
Electric Field ◽  
Piezoelectric Effect ◽  
Electrical Response ◽  
Host Material ◽  
Rubber Matrix ◽  
Electronic Components ◽  
Piezoelectric Structures ◽  
Microscopy Images

This paper deals with realization of multifunctional composite materials, having piezoelectric effect. First of all polymeric mats of electrospun piezoelectric nanofibers were realized with different geometries. Such effect has been maximized by designing properly the electrospinning apparatus in order to enhance the electric field in the interelectrodic space which polarize the dipolar moments. The mats are then integrated in a silicon rubber matrix and measurements of the electromechanical response of the composite materials thus manufactured are performed. A good integration of nanofibers inside the host material is evidenced by electron microscopy images, allowing delaminations, which could occur using piezoelectric films, to be avoided. A large electrical response to both impact and vibration stimuli has been finally demonstrated.

Novel method of electrical resistance measurement in structural composite materials for interfacial and dispersion evaluation with nano- and hetero-structures

2014 ◽  
Vol 1700 ◽  
pp. 37-46 ◽  
Author(s):  
Joung-Man Park ◽  
Dong-Jun Kwon ◽  
Zuo-Jia Wang ◽  
Joon-Hyung Byun ◽  
Hyung-Ik Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Composite Materials ◽  
Electrical Resistance ◽  
Interfacial Adhesion ◽  
Resistance Measurement ◽  
Electrical Resistance Measurement ◽  
Degree Of Dispersion ◽  
Uniform Dispersion ◽  
Reinforcing Fibers

ABSTRACTInterest in development in the use of nanoparticles in structural composites for the improvement of thermal conductivity, mechanical properties and electrical properties has recently stimulated some research efforts. Such improvements require the introduction of functional groups and the proper selection and concentration of the nanoparticles, as well as their uniform dispersion. The identification and verification of uniformity of dispersion is very important in the efficient processing for improved performance. Recently, new methods for studying and evaluating the interfacial properties between the reinforcing fibers and the epoxy matrix, have been developed. Distinct from FE-SEM observation, electrical resistance methods are being developed which can be applied for to measure interfacial shear strength (IFSS) and degree of dispersion. The main principle, on which the electrical resistance measurement is based, is Kirchhoff’s laws, which considers conductive materials as electrical circuits. In this research, the self sensing character of the conductive carbon nanotubes (CNT) and conventional carbon reinforcing fibers has been successfully used as a method for evaluating the dispersion of nanoparticles and interfacial adhesion. The electrical resistance in these composites was observed to be dependent on differences in wetting and interfacial adhesion between matrix and fillers. In summary, a correlation was observed between the electrical resistance and dispersion and degree of cure. It is felt that these methods, along with the electro-micromechanical methods, provide valuable tools for investigating the role of interfacial behavior on thermal conductivity, electrical and mechanical properties. Optical observations by FE-SEM of degree of dispersion and interfacial adhesion are consistent with the electrical resistance results. Additionally, it may be possible to use electrical resistance circuit analysis to detect the location of and extent of micro-damage within composite materials.

Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

1974 ◽  
Vol 32 ◽  
pp. 546-547
Author(s):  
R.R. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Composite Materials ◽  
Great Difficulty ◽  
Ion Milling ◽  
Transmission Electron ◽  
Ion Damage ◽  
Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

Resolution in photoelectron microscopy

1991 ◽  
Vol 49 ◽  
pp. 458-459
Author(s):  
G. F. Rempfer
Keyword(s):  
Electron Microscopy ◽  
Electric Field ◽  
Ultraviolet Light ◽  
Uniform Field ◽  
Virtual Image ◽  
Lens System ◽  
Photoemission Electron Microscopy ◽  
Planar Electrode ◽  
Electron Lens ◽  
Photoemission Electron

In photoelectron microscopy (PEM), also called photoemission electron microscopy (PEEM), the image is formed by electrons which have been liberated from the specimen by ultraviolet light. The electrons are accelerated by an electric field before being imaged by an electron lens system. The specimen is supported on a planar electrode (or the electrode itself may be the specimen), and the accelerating field is applied between the specimen, which serves as the cathode, and an anode. The accelerating field is essentially uniform except for microfields near the surface of the specimen and a diverging field near the anode aperture. The uniform field forms a virtual image of the specimen (virtual specimen) at unit lateral magnification, approximately twice as far from the anode as is the specimen. The diverging field at the anode aperture in turn forms a virtual image of the virtual specimen at magnification 2/3, at a distance from the anode of 4/3 the specimen distance. This demagnified virtual image is the object for the objective stage of the lens system.

Local Strengthening of EN AC-44200 Al Alloy with Ceramic Fibers

2015 ◽  
Vol 662 ◽  
pp. 237-240 ◽  
Author(s):  
Krzysztof Naplocha ◽  
Jacek W. Kaczmar ◽  
Jerzy Morgiel
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Composite Materials ◽  
Squeeze Casting ◽  
Porous Ceramic ◽  
Al Alloy ◽  
Ceramic Fibers ◽  
Ceramic Particles ◽  
Casting Technique ◽  
University Of Technology

The applied squeeze casting technique makes possible the local strengthening with ceramic fibers or ceramic particles of elements with Al-alloy matrices. In this paper the elaborated technology of manufacturing of porous ceramic preforms from Saffil fibers is shown and technology of squeeze casting elaborated at Wrocław University of Technology, Chair Foundry, Polymers and Automation described. There were applied the preforms characterized by porosities of 90% and 80%, what after squeeze casting with liquid EN AC - 44200 Al alloy produces the composite materials containing 10 vol. and 20 vol.% of fiber strengthening. The structural phenomena at the interface of strengthened alloy investigated with the optical and electron microscopy are discussed and the mechanical properties of manufactured composite materials are shown.

Design and Analysis of Hybrid Fused Filament Fabrication Apparatus for Fabrication of Composites

2021 ◽  
Vol 14 ◽  
Author(s):  
Aniket Yadav ◽  
Piyush Chohan ◽  
Ranvijay Kumar ◽  
Jasgurpreet Singh Chohan ◽  
Raman Kumar
Keyword(s):  
Additive Manufacturing ◽  
Composite Materials ◽  
Design Process ◽  
Low Cost ◽  
Matrix Material ◽  
Fabrication Process ◽  
Layer By Layer ◽  
Fused Filament Fabrication ◽  
Composite Manufacturing ◽  
Tool Paths

Background: Additive manufacturing is the most famous technology which requires materials or composites to be fabricated with layer by layer deposition strategy. Due to its lower cost, higher accuracy and less material wastage; this technology is used in almost every sector. But in many applications there is a need to alter the properties of a product in a certain direction with the help of some reinforcements. With the use of reinforcements, composite layers can be fabricated using additive manufacturing technique which will enhance the directional properties. A novel apparatus is designed to spray the reinforcement material into the printed structures in a very neat and precise manner. This spray nozzle is fully automated, which works according to tool-paths generated by slicing software. The alternate deposition of layers of reinforcement and build materials helped to fabricate customized composite products. Objective: The objective of present study is to design and analyze the working principle of novel technique which has been developed to fabricate composite materials using additive manufacturing. The apparatus is numerically controlled by computer according to CAD data which facilitates the deposition of alternate layers of reinforcement and matrix material. The major challenges during the design process and function of each component has been explored. Methods: The design process is initiated after comprehensive literature review performed to study previous composite manufacturing processes. The recent patents published by different patent offices of the world are studied in detail and analysis has been used to design a low cost composite fabrication apparatus. A liquid dispensing device comprises a storage tank attached with a pump and microprocessor. The microprocessor receives the signal from the computer as per tool paths generated by slicing software which decides the spray of reinforcements on polymer layers. The spraying apparatus moves in coordination with the primary nozzle of the Fused Filament Fabrication process. Results: The hybridization of Fused Filament Fabrication [process with metal spray process has been successfully performed. The apparatus facilitates the fabrication of low cost composite materials along with flexibility of complete customization of composite manufacturing process. The anisotropic behaviour of products can be easily controlled and managed during fabrication which can be used for different applications.

BIOSYNTHESIZED SILVER NANOPARTICLES USING CATHARANTHUS ROSEUS AND THEIR ANTIBACTERIAL EFFICACY IN SYNERGY WITH ANTIBIOTICS; A FUTURE ADVANCEMENT IN NANOMEDICINE

2021 ◽  
pp. 116-124
Author(s):  
MONIKA GUPTA
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Catharanthus Roseus ◽  
Leaf Extract ◽  
Research Work ◽  
Resistant Bacteria ◽  
Surface Plasmon Resonance Peak ◽  
Plasmon Resonance Peak ◽  
X Ray ◽  
Uniform Dispersion

Objective: This research work develops an approach to synthesize silver nanoparticles (AgNPs) by reduction of leaf extract of Catharanthus roseus plant. This study produces synthesized nanoparticles that have process-controlled attributes which make their antibiotic action highly efficient. These attributes include smaller size, proper morphology, uniform dispersion, metal ion content, and formation of functional groups. By optimizing the reduction process parameters, AgNPs gain the desired properties.  Methods: The biosynthesis of AgNPs process was performed using reaction of 10% (w/v) C. roseus leaf extract with AgNO3. The optimum conditions and concentration used for synthesis of nanoparticles were: 1 mM AgNO3, pH 5, and temperature 80°C with an incubation time of 72 h. All the above parameters were analyzed by ultraviolet-visible spectrophotometer with the surface plasmon resonance peak obtained at 440 nm. Results: Various characterization techniques were performed, namely, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, photoluminescence study, X-ray diffraction spectroscopy, Fourier transform infrared, dynamic light scattering, and atomic force microscopy. The results obtained from characterization confirmed the spherical morphology of the nanoparticles with size between 50 and 87 nm. In the current investigation, the antimicrobial activity of biosynthesized AgNPs was also determined using minimum inhibitory concentration and zone of inhibition methods against six different bacteria at different doses of AgNPs (100, 150, and 200 μg/ml) alone and also in combination with antibiotic-streptomycin. Conclusion: The results revealed that high concentration of AgNPs inhibits the bacterial growth. Furthermore, AgNPs revealed much stronger antibacterial action in synergy with streptomycin against antibiotic-resistant bacteria.

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