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Design equipment for measurement the surface wettability
Šubrt, Kamil ; Andrš, Ondřej (referee) ; Houška, Pavel (advisor)
This paper describes the design of equipment for measuring the wettability of surfaces. Surface wettability is determined by analyzing the profile drops, in an image taken with a digital camera. After the equipment is required to automatically find and focus the analyzed drops, taking the image, measuring wettability and save the image analysis, including measurement results to a file for subsequent offline analysis and archiving. The proposed facility is designed as a three-axis manipulator. For the driving the axes are chosen stepper motors. A key factor in achieving the highest possible speed measurement is very smooth movement of the manipulator, which is achieved by controlling of motors in microstepping mode with very high resolution. Software entire system is designed in the NI LabVIEW development environment for image processing was used module NI Vision.
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Measurement of surface tension for surface characterization of advanced ceramic materials
Mišáková, Liliana ; Kachlík, Martin (referee) ; Salamon, David (advisor)
Povrchy inorganických materiálov, zvlášť kovov alebo kovových oxidov, ktoré sú často charakteristické vysokou povrchovou energiou, sú zvyčajne kontaminované adsorbovanými organickými molekulami. Tieto molekuly majú na povrchy zväčša nepriaznivý vplyv, do značnej miery napríklad ovplyvňujú funkcionalitu a výkonnosť polovodičov a znemožňujú, prípadne sťažujú prevedenie povrchových úprav na povrchoch kovov aj keramík. Taktiež majú nepriaznivý vplyv na priľnavosť. Adsorbované častice spôsobujú znižovanie hydrofilicity povrchu. Hydrofilicita, adhezivita a zmáčavosť povrchu sa veľmi dobre posudzujú prostredníctvom merania kontaktného uhlu. V tejto práci je značná pozornosť venovaná práve meraniu statického kontaktného uhlu. [10] Samotné meranie kontaktného uhlu je možné vykonať rôznymi spôsobmi, v tejto práci bol však použitý najvhodnejší prístup, a to metódou „sessile-drop“, teda pokladanej alebo depozitovanej kvapky na meraný povrch. K meraniu bol využitý klasický „sessile-drop goniometer“, teda aparatúra, ktorá pozostávala z nastaviteľného stojanu na vzorky, nad ktorým bol umiestnený zdroj svetla, a objektívu fotoaparátu, ktorý bol prepojený s kamerou zabudovaného smartfónu. Meranie prebiehalo tak, že kvapka s objemom 3L destilovanej superčistej vody bola depozitovaná na povrch substrátu pomocou mikroinjekčnej striekačky. Cieľom tejto práce bolo nielen stanoviť kontaktné uhly a porovnať ich hodnoty medzi rôznymi typmi materiálov navzájom a po upravách tepelného a/lebo chemického charakteru. Vyhodnotené údaje zachycovali zmeny, ku ktorým došlo na povrchoch daných keramických materiálov pri adsorpcii organických molekúl. Proces tepelnej úpravy (kalcinácia na teplote 800°C, následne pokles na teplotu 600°C, po celkovú dobu 16 hodín) bol aplikovaný na všetkých typoch vzoriek, kde niektoré sa medzi sebou líšili teplotou slinovania. Ihneď po kalcinácii boli vzorky podrobené meraniu kontaktných uhlov, z ktorého jasne vyplynulo, že hydrofilicita a zmáčavosť povrchu sa zvýšila. Tento jav bol pozorovaný na všetkých vzorkách, a na všetkých vzorkách sa hodnoty kontaktného uhlu líšili veľmi významne od hodnoty, ktorá bola získaná v tzv. primárnom meraní. Všetky detailné hodnoty a vyhodnotené výsledky sú posudzované v časti diskusia. Ďalšou úpravou povrchu, ktorá bola vykonaná na vybraných vzorkách, bolo čistenie povrchu etanolom. Proces bol opäť realizovaný na všetkých vzorkách. Potom, ako boli zrealizované všetky merania na kalcinovaných vzorkách, boli všetky tieto vzorky ponorené do etanolu na približne 2 hodiny. Po vybratí vzoriek a ich osušení na vzduchu boli uskutočnené ďalšie merania kontaktných uhlov. Výsledky priniesli opäť rozdielne hodnoty v porovnaní s predchádzajúcimi meraniami a sú rozvinuté v časti diskusia.
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Electrochemical Characterization of Nanostructured Surfaces Modified by Substancies with Thiol Bound
Urbánková, Kateřina ; Kynclová, Hana (referee) ; Hrdý, Radim (advisor)
This master thesis deals with nanotechnology, nanoparticles and nanostructured surfaces, electrochemical methods, especially voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy and contact angle measurement. One part is focused on electrodes primarily nanostructured and modified by substancies with thiol bound. Tutorial for preparation of gold nanostructured electrods is introduced in practical section including SEM photos of electrode surface. Nanostructured and bare gold electrodes were modified by 11-mercaptoundecanoic acid, streptavidin, glycine and biotin and measured by cyclic voltammetry, electrochemical impedance spectroscopy and contact angle.
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Automated optical measurement of drops contact angle
Dugáček, Ján ; Richter, Miloslav (referee) ; Petyovský, Petr (advisor)
Measurement of surface tension of solids usually requires manual processing of photographs of droplets of liquids with known properties on the measured material's surface, during which the contact angle is manually determined. The objective of this work is to implement an algorithm that can determine these contact angles from photographs and does not require the photographs to be made under specific light conditions. The implementation cannot depend on paid libraries and must be simple to incorporate into existing software.
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Optimization of electrochemical sensor for detection in microvolume
Gajdoš, Libor ; Pekárek, Jan (referee) ; Prášek, Jan (advisor)
This thesis describes optimization and modification of standard thick-film electrochemical sensor to be able to be used for detection in microvolumes. In the theoretical part, the thick film technology is described. The work is then focused on the wettability of surfaces followed by introduction to electrochemistry and electro-analytical methods. In the experimental part, screen-printing of various types of thick film pastes on ceramic substrates for determination of their wettability and the following modification of the sensors with thick-film paste and with Parylene vaporization can be found, as well as the basic electrochemical measurements in microvolume using the modified sensor. Finally the results are summarized in conclusion.
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Study of possibilities of increasing the biocompatibility of organic semiconductor surfaces
Malečková, Romana ; Šafaříková, Eva (referee) ; Vala, Martin (advisor)
This bachelor thesis deals with the possibility of biocompatibilization of organic semiconducting polymer PEDOT:PSS using RGD peptide for the construction of biosensors. Samples were prepared and compared where the RGD peptide was bound directly, as well as samples with a peptide bound via crosslinker molecule sulfo-SANPAH. Whether the RGD peptide was bound to the substrate was determined by the method of measuring the contact angle of liquids with subsequent calculation of surface energy. The results were further verified by elemental analysis, infrared spectrometry and Raman spectroscopy.
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Fixed-charge examination by surface energy measurement
Mojrová, Barbora ; Boušek, Jaroslav (referee) ; Hégr, Ondřej (advisor)
This work is deal with development of alternative method measuring fixed charge in thin dielectric layers by surface tension. Presence fixed charge takes effect so-called Back Surface Field (BFS), which helps to decrease surface recombination velocity on back side of solar cell. In work is described experimental measuring on dielectric layers Al2O3, AlN, SiNx, Y2O3 and PSG deposit on crystalline silicon wafers. Surface tension (it is the same like surface free energy) is analyzed from contact angle size using See System.
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Study of relation between conditions of the test FNCT (Full Notched Creep) and the rate of crack grow SCG (Slow Crack Growth) for evaluating HDPE cut growth resistance
Porubský, Tomáš ; Sadílek, Jiří (referee) ; Petrůj, Jaroslav (advisor)
Theoretical part of this thesis presents summary of material and testing parameters which influence SCG and consequently the duration of the FNCT test. The experimental part focuses on modification of testing conditions of FNCT test in order to minimize the test time. FNCT tests were performed for four types of surfactants: Arkopal N110, Sodium dodecylbenzensulfonate (NaDBS), Disponil LDBS55 and Simulsol SL8. The most pronounced accelerating effect was observed for NaDBS surfactant, which in comparsion with commonly used Arkopal N110 doubled the test speed at the same concentration (11 %) and other test conditions. The accelerating effect of NaDBS was also observed for two different PE grades: Liten VB85 and VL 20N. Under the test conditions 80 °C and 4 MPa, 5% NaDBS water solution caused for VL 20N almost 12,5-fold acceleration compared to conventional 2% Arkopal N110 and almost 8,5-fold acceleration for VB 85. The correlation between wettability of surfactant solution and FNCT time to fracture was found.
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