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Nanoteknik i textilier : För framtidens arbetskläder i hemtjänstenNILSSON, MALIN, MUNKBO, January 2013 (has links)
Det har blivit allt vanligare att sjukvården i Sverige flyttas ut till vårdtagarnas hem. De kan med hjälp av hemtjänst få bo kvar i sina egna hus längre men samtidigt få den hjälp de behöver. År 2007 använde sig totalt 153 723 personer av dessa tjänster runt om i Sverige. De plagg som personalen bär utsätts för många olika typer av yttre påfrestningar vid hembesök hos vårdtagarna. Smittspridning inom vården sker främst via personalens händer och kläder.Nanoteknologi är en framväxande teknik som gått på högvarv inom många olika områden under det senaste årtiondet. Forskning pågår som involverar nanoteknologi för att förbättra egenskaper eller för att skapa funktionella textilier som kan få egenskaper som antibakteriella, lättrengörliga, vatten- och fläckavvisande samt luktfria. Syftet är att underska om nanoteknik kan användas i det textila materialet i arbetskläder inom hemtjänsten för att bättre stå emot yttre påfrestningar. Det finns idag många problem inom området arbetskläder och hygien, vi vill därför undersöka om denna teknik kan vara en av lösningarna.Nanoteknik för textilier har två inriktningar. Den ena strävar främst efter att använda nanostorleken för att skapa nanostrukturer under själva tillverkningsprocessen, medan den andra är inriktad mot ytbehandlingsprocesser. I rapporten ligger fokus på beläggningsmetoden och de självrengörande och antibakteriella egenskaperna som kan skapas hos ett material.Vi kom fram till att det bästa alternativet för dessa typer av plagg skulle vara att tillföra antibakteriella egenskaper. De kan då beläggas med antingen titandioxid, zinkoxid eller silver då det är väl beprövade ämnen som är bevisade att fungera och ger just dessa egenskaper.Med hjälp av empiriska undersökningar kunde vi ge svar på vad arbetskläder utsätts för under en arbetsdag. Utifrån dessa resultat kunde vi rikta in vår teoretiska referensram på de områden som skulle kunna vara intressanta för att uppnå syftet. Tillslut kom vi fram till att nanoteknik kan bidra till att skapa kläder som bättre står emot yttre påfrestningar och ger bättre hygieniska förhållande / Program: Textil produktutveckling och entreprenörskap
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Självsanerande ytbeläggning i nanostruktur : Är det möjligt att applicera på elektrooptiska sensorer och till vilken nytta?Berg, Magnus January 2009 (has links)
<p>Då marina enheter numera deltar i internationella missioner, kommer den nya miljön som enheterna opererar i att påverka bland annat deras sensorer.</p><p>Den här studien avhandlar några av de nu framtagna självsanerande ytbeläggningarna och ger en presentation av hur de fungerar på några marina elektrooptiska sensorers yttersta linser.</p><p>Studien försöker ge svar på ytbeläggningarnas transmittans och hur effektivt de kan sanera bort oönskade saltlager tillsammans med andra nedsmutsande partiklar från sensorlinserna samt den militära nyttan av att använda självsanerande ytbeläggning.</p> / <p>This study deals with now developed self-cleaning coatings and gives a presentation of how they work on some electro-optical sensor lenses used in the navy. The study also examines the coatings transmittance and how efficient they can clean the sensor lenses from undesired salt layers and other soiling particles.</p><p>After the introduction the study presents basic facts of the chosen sensors, nanotechnology, surface wettability and also salts and salinity. Thereafter the study describes current nano-research on self-cleaning coatings and possible results there of, when the coatings are applied on the different sensors.</p><p>In the study I give my opinion of the military benefit of using self-cleaning coatings, which from a general point of view is that there mostly are positive effects using such a coating, in a technical perspective.</p><p>The study ends with conclusions that there are self-cleaning coatings based on TiO<sub>2</sub>-nanoparticles which can transmit within the visual spectra and also can clean undesired soiling particles. But can not confirm that these coatings have the desired effect on salt crystals, or transmit within wavelengths spectrum for IR-detectors and lasers.</p> / ChpT 08-10
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Kinetic Monte-Carlo studies of island shape evolution on weakly-interacting substratesThunström, Filip January 2018 (has links)
Metal thin films deposited on weakly-interacting substrates constitute an essential element of numerous microelectronic, catalytic, and optical devices. However, the natural tendency of metal atoms to agglomerate, upon condensation on a weakly-interacting surface, in dispersed three-dimensional (3D) islands affects negatively the performance of the above-mentioned devices. The aim of this thesis is to investigate one of the mechanisms governing silver (Ag) 3D island growth on weakly-interacting substrates, i.e. the nucleation of a new layer on the island top. Kinetic Monte Carlo (KMC) simulations are employed to calculate the top island-layer critical radius Rc required for nucleating a new layer in the out-of-plane direction. Single-island simulations are performed for growth temperatures T in the range 250 to 500 K and ratios of the pairwise adatom/substrate atom bond strength EB,sub to the corresponding adatom/adatom value EB,film in the range 0.5 to 0.75. We find that for T values below 250 K the islands exhibit a 2D morphology for all EB,sub/EB,film ratios. In contrast, for T values above 300 K there exists a range of relatively small EB,sub/EB,film values, where 2D morphology dominates. To calculate Rc for each island layer as the island shape evolves, a subroutine is developed and implemented in an existing KMC algorithm. Rc values are computed for 3D island growth at EB,sub/EB,film = 0.5 in the T range 300−500 K and the results show that Rc decreases monotonously from 17.3 to 6.0 Å and saturates approximately at 375 K. This trend is opposite to the typical behavior of islands grown under homoepitaxial conditions, for which the enhancement of downward inter-layer diffusion caused by an increase of T leads to lower atomic densities on the top, i.e. to a lower nucleation probability, and thus to an increase of Rc. This work contributes to the understanding of the physical processes that control thin-film morphological evolution; which is paramount for controlling and manipulating film growth for specific applications.
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Studies on Radiation-induced Defects in InP/InAsP Nanowire-based Quantum Disc-in wire PhotodetectorsMansouri, Ebrahim January 2018 (has links)
Photodetectors are used in many applications such as digital and thermal cameras or in solar panels. They can also be designed to detect the omnipresent high-energy radiation/particles, and for radiation imaging in biomedical applications. Novel nanostructures offer significant advantages compared to traditional designs for the realization of fast, sensitive, compact and cheap sensors and efficient solar cells. Examples of such nanostructures include quantum dots (QDs), quantum wells (QWs) and NW arrays. This thesis is devoted to experimental investigations of effects of high-energy (1 MeV) protons on the optical and electrical performance of InP/InAsP NW-based QDiscs-in wire photodetectors. The proton-induced degradation of the optical performance has been studied by means of Fourier Transform Infrared (FTIR) photocurrent spectroscopy. The spectrally resolved photocurrent (PC) and current-voltage (I-V) characteristics were measured at low temperature (5 K and 77K) and at room temperature (300K) before and after 1 MeV proton irradiation under vacuum conditions with fluences ranging from 1.0×1012–3.0×1013 cm-2. The particle radiation exposure has been done in the Ion Beam Accelerator at the Department of Nuclear Physics Department at Lund University. Considering both PC and I-V characteristics, it was found that the devices were sensitive to all proton irradiation at all fluences. In general, the PC intensity significantly increased after radiation for all fluences, however, a week after exposure the PC and dark current gradually recovered. At 3×1012 p/cm2 fluence level, it was figured out that photocurrent which attributed to QDiscs disappeared for a couple of days after exposure, however, over time and gradually, those started to manifest again even at low and room temperatures, causing radiation-induced changes in device parameters to be time-dependent; however, it was not recorded any signals related to QDiscs at fluence of 3×1013 p/cm2. Substantial changes in the dark I-V characteristics, as well as increases in the dark current, are observed after irradiation. The influence of proton irradiation on light and dark current characteristics also indicated that NW structures are a good potential candidate for radiation harsh-environment applications. It was also observed a significant increase in dark current after the radiation for all devices, however, by applying the voltage to the photodetectors, the PC and I-V characteristics gradually being to diminish, which may be attributed to an annealing process.
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Nanoparticle Removal and Brownian Diffusion by Virus Removal Filters: Theoretical and Experimental StudyGustafsson, Olof January 2017 (has links)
This study aims to examine the throughput of nanoparticles through a Cladophora cellulose based virus removal filter. The effect of Brownian motion and flow velocity on the retention of 5 nm gold nanoparticles, 12.8 nm dextran nanoparticles and 28 nm ΦX174 bacteriophages was examined through MATLAB simulations and filtration experiments. Modeling of Brownian motion at different flow velocities was performed in MATLAB by solving the Langevin equation for particle position and velocity for all three types of particles. The motion of all three particle types was shown to be constrained at local flow velocities of 1∙10-2 m/s or greater. The constraint was greatest for ΦX174 bacteriophages, followed by dextran particles and then gold particles as a result of particle diameter. To verify the effect experimentally, virus removal filters were prepared with a peak pore width of 23 nm. Filtration experiments were performed at different flux values where gold and dextran particles did not exhibit any difference in retention between fluxes. However, a significant amount of gold and dextran particles were removed by the filter despite being smaller than the measured pore size. A decrease in retention with filtrated volume was observed for both particle types. Filtration of ΦX174 bacteriophages exhibited a difference in retention at different fluxes, where all bacteriophages where removed at a higher flux. The results from both simulations and experiments suggest that the retentive mechanism in filtering is more complex than what can be described only by size exclusion sieving, Brownian diffusion and hydrodynamic constraint of particles.
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Functionalization, Characterization and Applications of Oxidized Nanocellulose DerivativesRuan, Chang-Qing January 2017 (has links)
Cellulose, a sustainable raw material derived from nature, can be used for various applications following its functionalization and oxidation. Nanocellulose, inheriting the properties of cellulose, can offer new properties due to nanoscale effects, in terms of high specific surface area and porosity. The oxidation of cellulose can provide more active sites on the cellulose chains, improving its functionalization and broadening applications. Two kinds of oxidation and their corresponding applications are described in this thesis: periodate oxidation and Oxone® oxidation. 2,3-dialdehyde cellulose (DAC) beads were prepared from Cladophora nanocellulose via periodate oxidation, and were further modified with amines via reductive amination. Several diamines were selected as possible crosslinkers to produce porous DAC beads, which showed higher porosity, stability in alkaline solution and enhanced thermal stability. After functionalization of DAC beads with L-cysteine (DAC-LC), thiol, amine and carboxyl groups were introduced into the DAC beads, endowing the DAC-LC beads with high adsorption capacity for palladium. The synthesized DAC-LC beads were characterized with SEM, FTIR, XPS, TGA, BET and XRD and the palladium adsorption process was investigated. Chitosan was employed as a crosslinker in functionalization of DAC beads (DAC-CS). The conditions for the synthesis of DAC-CS beads were screened and verifying the stability of the beads in alkaline solution. The DAC-CS beads produced were investigated using SEM, FTIR, XPS, TGA and BET, and the adsorption and desorption capacity of Congo red was studied, indicating DAC-CS beads have potential as sorbent. Oxone oxidation of cellulose is a novel one-pot oxidation method in which mainly the hydroxyl groups on C6 are oxidized to produce carboxylic acid groups on the cellulose chains. To increase the efficiency of Oxone oxidation, several reaction parameters were studied. Cellulose pulp and Cladophora nanocellulose were chosen as prototypes to investigate the effects of oxidation, and the physicochemical properties of the oxidized products were characterized. Cellulose pulp, pretreated with Oxone oxidation, was disintegrated by homogenization to prepare cellulose nanofibers (CNF). The effect of pretreatment on the preparation of CNF was studied, and the results indicated that Oxone oxidation was efficient in the production of CNF.
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Graphene Growth through Chemical Vapor Deposition - Optimization of Growth and Transfer ParametersOlsson, Adam January 2017 (has links)
The goal of this thesis work is to investigate the possibility to grow graphene by Chemical Vapor Deposition (CVD) on copper foil with acetylene as a precursor and varigon (5\% H$_2$ in Ar) as a carrier gas. The possibility of nitrogen doping by ammonia treatment during the growth process is also investigated. The possibility of graphene transfer, with the use of Poly(Methyl Metacrylate) (PMMA), from the copper onto another target substrate, Flourine doped Tin Oxide (FTO), is also explored. The main technique of characterization of the grown and transfered graphene is Raman spectroscopy, a great tool for investigating the number of graphene layers and amount of defects. Other characterization methods used are Scanning Electron Microscopy (SEM) X-ray Photoelectron Spectroscopy (XPS) to investigate morphology and elemental composition, respectively. The result of this thesis study is that graphene growth is entirely possible with acetylene as a precursor, as shown by the Raman spectroscopy, XPS and SEM. The grown graphene has a high quality with few layers and a low number of defects. The ammonia treatment, however, doesn't seem to have an immediate effect on the graphene growth. The XPS data indicates that there are no nitrogen doping in the graphene, though there might be a correlation between the ammonia and the number of layers, but further investigations has to be made. Transfer is also proven possible with the method developed. However, improvements to the transfer method can be done since there are both larger tares, caused by the transfer onto the FTO, as well as microscopic tares, possibly caused by thermal expansion of the PMMA.
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Heavy metal removal and water treatment using UpsaliteErenbo, Philip January 2017 (has links)
Ion exchange reactions between Upsalite, a mesoporous magnesium carbonate, and metal ions of cadmium, lead and nickel have been studied to evaluate the capacities of Upsalite as a water treatment agent. Uptake capacity and reaction kinetics have been evaluated using a batch experiment and atomic absorption spectroscopy. Post reaction materials from the reaction between Upsalite and each of the three metal ions have been investigated with XRD, SEM and TGA in order to determine what species have been formed during the ion exchange. The maximum uptake capacity of Upsalite was found to be 990 mg/g for cadmium ions and 470 mg/g for nickel ions. The evaluation of the uptake capacity of lead ions in Upsalite was not conclusive but the results indicate a maximum uptake capacity of at least 4400 mg/g. The uptake capacity for lead ions is to high be explained by ion exchange alone and is proposed to be from both ion exchange and adsorption. The reaction between Upsalite and cadmium ions resulted in the formation of crystalline CdCO3 (Otavite) with some parts of MgCO3 and crystalline MgO remaining from the original material. Post reaction materials from the reaction between nickel ions and Upsalite were found to be amorphous and contained both MgCO3 and crystalline MgO. The reaction between Upsalite and lead ions resulted in crystalline hydrocerussite (Pb3(CO3)2(OH)2).
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Plasmonic Effect of Metal Nanoparticles Deposited on Wide-Band Gap Metal Oxide Nanowire SubstrateGilzad Kohan, Mojtaba January 2017 (has links)
The application of nanowires (NWs) in solar cells (SCs) is of great interest due to their new promising aspects established in nanoelectronics. Semiconductors associated with plasmonic metal nanoparticles (NPs) such as Silver (Ag), Gold (Au) and Copper (Cu), show enhanced performance in solid state light absorbing SCs owing to plasmonic characteristic of noble metal NPs. Plasmonic NPs presented a significant role in development of visible light harvesting for many applications such as photocatalytic materials, photodynamic in Surface Enhanced Raman Spectroscopy (SERS) and photovoltaics (PVs). Integration of plasmonic NPs in semiconductor materials have opened the routes to expand new PV systems with high efficiency light absorption. In this project, we introduce the synthesis ZnO and TiO2 NWs used as N-type semiconducting substrates and various methods for isolating plasmonic metal NPs, which are later deposited on the semiconducting substrates. Vertically aligned ZnO and TiO2 NWs arrays were grown on the fluorine-doped tin oxide (FTO) conductive glass substrates via hydrothermal method at low temperature and the plasmonic NPs were synthesized by wet chemistry procedures and finally decorated on the NW films by using electrophoretic deposition. The impact of metal NPs loaded on the ZnO and TiO2 NWs substrates was studied by means of UV-vis spectroscopy and Photoluminescence (PL) spectroscopy. The absorbance spectra of individual NPs were recorded. Remarkably, the reflectance spectra of produced samples presented an enhancement in light absorption of the substrates after uptake of NPs on the ZnO and TiO2 NWs. The optical properties of the as grown ZnO NWs films decorated with Ag NPs (I) in direct contact with substrate and (II) in presence of an Al2O3 insulating spacer layer have been investigated. Both systems exhibited an enhancement in the UV band-edge emission from the ZnO when excited at 325 nm. In contrast, the broad bend defect emission of the samples did not have a significant change compare to bare ZnO substrates. The observed results suggested that the ZnO and TiO2 NWs decorated with plasmonic nanoparticles can boost the optical properties of MOs NWs substrates and hence effectively enhance the separation of photoexcited electron-hole pairs and photo-conversion applications.
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Syntes av hydroxyapatit/ nanocellulosa kompositer / Synthesis of Hydroxyapatite/Nanocellulose CompositesISHIKAWA, MAI January 2014 (has links)
Cellulose nanocrystals (CNC) are great candidates for composite materials. The reasons why CNCs are such attractive materials for them are due to their great mechanical properties, high aspect ratio and low density. On the other hand, hydroxyapatite (HAp) is a kind of calcium phosphate and a main component of bones and teeth. The purpose of the present study is to make oriented nano-sized composites with CNC and HAp. Although some researchers carried out to make CNC composites with HAp for biomedical materials, nano-sized and oriented ones haven’t been achieved yet. Also, films made of CNC and other compounds are known to be transparent and have good oxygen permeability. Especially when CNCs’ direction is in parallel, they show high strength. However most previous researches dealt with particles or plate-like minerals in inorganic/CNC films, so there is no case that coated CNCs themselves were aligned in the films. Therefore fabrication of composite-oriented thin films is quite unique and it will be a potential step for bone-like hierarchical structure. In experiment, certain amount of CNC suspension with functional groups were put into revised simulated body fluid (r-SBF) solutions which were adjusted between pH 6.9-7.9 to make the molar ratio of calcium ion per functional groups on CNC surfaces between 30-230. The suspensions were put into the ultrasonic bath for 15 minutes and stirred in the thermostatic oven at 37 ⁰C for 1 hour. The process of ultrasound and stirring in oven was repeated 1-3 times depending on conditions. Precipitated products were collected with the centrifuge instrument and dried with the freeze dryer. Functional groups induced HAp’s nucleation and the HAp/CNC composites could be obtained under control of molar ratio of calcium ions per functional groups on CNC and pH. Morphology of the composites could be determined by pH and HAp content could be controlled between 25-75 wt% by initial molar ratio. The suspension having the composites synthesized in pH 7.9 with low initial molar ratio was dropped on superhydrophilic glass substrates. At the moment, the substrates were set with leans of 20 degrees. Then they were dried at 60 oC for 3 hours and transparent films containing 25-40 wt% of HAp were obtained. The transmittances of the films were more than 90 % and their thicknesses were 2.2-4.2 μm. The films were suggested to have oriented structure by polarization microscope when the shape of the composites were needle-like homogeneously and independent each other. From the results from SEM, they were aligned longitudinally at both ends of the film and laterally at the upper middle part of the films. It is considered that controlling drying direction influenced on the orientation. The current study should become a promising step to build up a bone-like hierarchical structure artificially.
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