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Pvdf —AN Ideal Candidate For Use In Nanogenerators
Pisarenko, Tatiana
In this work, the PVDF composite, also known as polyvinylidene fluoride in the formof thin nanofibres, was created. Subsequently, a single-fibre characterization was performed, whichproves its piezoelectric properties and describes its structure. Electron microscopy, atomic forcemicroscopy and X-ray photoelectron spectroscopy were chosen as characterization methods. Thediscussion in this paper deals with the ability of these fibres to use PVDF as a nanogenerator.
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Characterization Of Pvdf Nanofibers Created By The Electrospinning Method
Pisarenko, Tatiana
The work investigates structure and properties of composite fibers created by the electrospinning method for piezoapplications. Polyvinylidene fluoride (PVDF) was used as a precursor. As an electrospining parameter, the collector speed of 300 and 2000 rpm was selected, which significantly affects the properties of nanofibers. The structure of fibers was investigated by scanning electron microscopy (SEM) using focused ion beam (FIB). Morphology and piezoelectric domains was observed using piezoresponse force microscopy (PFM). Phase composition was identified using Raman spectroscopy and by Fourier-transform infrared spectroscopy (FTIR). Found results are essential for the design and construction of piezoelectric based structures.
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Characterization of PVDF material in nanoscale resolution
Pisarenko, Tatiana ; Dallaev, Rashid (referee) ; Sobola, Dinara (advisor)
Tato práce se zabývá charakterizací nanovláken na bázi polyvinylidenfluoridu. Zaměření práce je na piezoelektrické vlastnosti vlákna, které jsou studovány metodou piezoelektrické silové mikroskopie. Takto byly měřeny dva typy odlišných vzorků, které se lišily v parametrech výroby. Odlišnosti vláken v jejich fázovém složení byly také zkoumány za využití Ramanovy spektroskopie a infračervené spektroskopie s Fourierovou transformací. Chemická analýza povrchu a jeho stavu proběhla pomocí rentgenové fotoelektronové spektroskopie. Různé uspořádání nanovláken spolu s jejich průřezem bylo pozorováno rastrovacím elektronovým mikroskopem za využití fokusovaného iontového svazku. Rovněž byla zkoumána smáčivost a kontaktní úhel povrchu vzorků s demineralizovanou vodou. Bylo zjištěno, že vyšší rychlost otáček válce během procesu elektrostatického zvlákňování má velmi významný vliv na jejich uspořádání a tím i na parametry ovlivňující tvorbu piezoelektrického jevu a dalších materiálových vlastností.
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Electrospun fibers based on PVDF and nylon
Černohorský, Petr ; Sobola, Dinara (referee) ; Papež, Nikola (advisor)
Polymer nanofibers used for the construction of triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) are new and promising technologies for energy recovery. Thanks to the generation of electrical energy based on mechanical movement (deformation), these fibers can find application in the field of self-powered electronic devices. In this work, three nanofibrous structures of materials were prepared by electrostatic spinning: pure polyvinylidene fluoride (PVDF), pure polyamide-6 (PA6) and their mixed combination PVDF / PA6. Non-destructive analyzes such as Raman spectroscopy, FTIR, XPS and electron microscopy were used to study the properties of nanofibers. Analyzes confirmed the positive effect of electrostatic spinning of polymers on the support of the formation of highly polar crystalline -phase in PVDF and , -phase in PA6. The structure arrangement of the nanofibrous material and their defects were observed by scanning electron microscopy (SEM). Furthermore, the contact angle of the wettability of the liquid on the surface was measured for the materials, and the permittivity was measured to monitor the dielectric properties. The described results make the mixed material PVDF / PA6 very promising for further research in the field of nanogenerators and functional textiles.
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Design of tester of piezoelectric PVDF layers
Sijková, Simona ; Rubeš, Ondřej (referee) ; Hadaš, Zdeněk (advisor)
The diploma thesis deals with a design of a tester device, a selection and verification of a suitable method for comparing the piezoelectric properties of tested PVDF samples. In the introduction, a basic overview of the theory is important to understand the issue and the various branches of use of PVDF in the field of energy harvesting. The tester device includes a unimorph piezoelectric cantilever beam with tip mass, whose properties are described by three models: a model with N degrees of freedom reduced to one degree of freedom (NDOF), a single degree of freedom model (SDOF), both created in Matlab and a model for verifying results in FEM ANSYS Workbench program. The voltage time response and the voltage frequency response of the models is compared with each other. For two different PVDF samples, the voltage response to harmonic excitation is measured using a tester device, and the piezoelectric properties of one of them are determined using the NDOF and SDOF models.
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Development of PVDF nanofibers sensor
Klásek, Matyáš ; Tofel, Pavel (referee) ; Hadaš, Zdeněk (advisor)
This diploma thesis deals with the feasibility of using PVDF nanofibers as an active sensor layer generating electrical signal. PVDF and related electromechanical effects are described. A research study is conducted regarding existing PVDF nanofiber applications and based on it, an event sensor design utilizing triboelectric effect and electrostatic induction is proposed. The electrical response of the layers is experimentally investigated and a pulse detection algorithm is conceived and implemented. Finally, a way of integrating the sensor into a rail track is proposed.
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Measurement of energy harvesters
Kašpárek, Ondřej ; Pikula, Stanislav (referee) ; Kunz, Jan (advisor)
Over recent years the power outputs of piezoelectric energy harvesters have increased to the point where they rival other types of energy harvesting and therefore their sufficient parameterization is necessary. Four piezoelectric PVDF films - DT1-028KL, DT1-052K, DT2-028K a LDT2-028K made by SENZOR SOLUTIONS TE Connectivity were parametrized by two created systems of measurement with force strain. Power outputs of these films when pressed with harmonic force signal with 3 Nrms amplitude are in nW and transferred energies after force impulse with size 300 N are between hundreds and tenths of fJ. Furthermore, values of quality factor, resonance frequency, optimal load resistance and maximal power stability were determined.
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Tracking Resistance Of
Various Materials In Vacuum
Šedivý, Matúš
Many vacuum instruments used in industry and scientific research apply high voltage components. Vacuum performs as an insulator with theoretically infinite breakdown voltage. Surface of dielectrics between two electrodes inside a vacuum chamber is the weakest link for a possible electrical breakdown (tracking). This paper focuses on examination of a vacuum pressure influence to the surface breakdown voltage of a various materials. Results were compared and led to determination of an appropriate materials for a design of internal connectors in electron microscopes produced by the company Thermo Fisher Scientific.
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