• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • Tagged with
  • 6
  • 6
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

3-D modeling of shallow-water carbonate systems : a scale-dependent approach based on quantitative outcrop studies

Amour, Frédéric January 2013 (has links)
The study of outcrop modeling is located at the interface between two fields of expertise, Sedimentology and Computing Geoscience, which respectively investigates and simulates geological heterogeneity observed in the sedimentary record. During the last past years, modeling tools and techniques were constantly improved. In parallel, the study of Phanerozoic carbonate deposits emphasized the common occurrence of a random facies distribution along single depositional domain. Although both fields of expertise are intrinsically linked during outcrop simulation, their respective advances have not been combined in literature to enhance carbonate modeling studies. The present study re-examines the modeling strategy adapted to the simulation of shallow-water carbonate systems, based on a close relationship between field sedimentology and modeling capabilities. In the present study, the evaluation of three commonly used algorithms Truncated Gaussian Simulation (TGSim), Sequential Indicator Simulation (SISim), and Indicator Kriging (IK), were performed for the first time using visual and quantitative comparisons on an ideally suited carbonate outcrop. The results show that the heterogeneity of carbonate rocks cannot be fully simulated using one single algorithm. The operating mode of each algorithm involves capabilities as well as drawbacks that are not capable to match all field observations carried out across the modeling area. Two end members in the spectrum of carbonate depositional settings, a low-angle Jurassic ramp (High Atlas, Morocco) and a Triassic isolated platform (Dolomites, Italy), were investigated to obtain a complete overview of the geological heterogeneity in shallow-water carbonate systems. Field sedimentology and statistical analysis performed on the type, morphology, distribution, and association of carbonate bodies and combined with palaeodepositional reconstructions, emphasize similar results. At the basin scale (x 1 km), facies association, composed of facies recording similar depositional conditions, displays linear and ordered transitions between depositional domains. Contrarily, at the bedding scale (x 0.1 km), individual lithofacies type shows a mosaic-like distribution consisting of an arrangement of spatially independent lithofacies bodies along the depositional profile. The increase of spatial disorder from the basin to bedding scale results from the influence of autocyclic factors on the transport and deposition of carbonate sediments. Scale-dependent types of carbonate heterogeneity are linked with the evaluation of algorithms in order to establish a modeling strategy that considers both the sedimentary characteristics of the outcrop and the modeling capabilities. A surface-based modeling approach was used to model depositional sequences. Facies associations were populated using TGSim to preserve ordered trends between depositional domains. At the lithofacies scale, a fully stochastic approach with SISim was applied to simulate a mosaic-like lithofacies distribution. This new workflow is designed to improve the simulation of carbonate rocks, based on the modeling of each scale of heterogeneity individually. Contrarily to simulation methods applied in literature, the present study considers that the use of one single simulation technique is unlikely to correctly model the natural patterns and variability of carbonate rocks. The implementation of different techniques customized for each level of the stratigraphic hierarchy provides the essential computing flexibility to model carbonate systems. Closer feedback between advances carried out in the field of Sedimentology and Computing Geoscience should be promoted during future outcrop simulations for the enhancement of 3-D geological models. / Das Modellieren von geologischen Aufschlüssen liegt der Schnittstelle zwischen zwei geo-logischen Teildisziplinen, der Sedimentologie und der geologischen Modellierung. Hierbei werden geologische Heterogenitäten untersucht und simuliert, welche im Aufschluss beobachtet wurden. Während der letzten Jahre haben sich die Werkzeuge und die Technik der Modellierung stetig weiter-entwickelt. Parallel dazu hat die Untersuchung der phanerozoischen Karbonatablagerungen ihren Fokus auf gemeinsamen Vorkommen von zufälligen Faziesverteilungen in beiden Ablagerungs-gebieten. Obwohl beide Teildisziplinen durch die Aufschlussmodellierung eigentlich verbunden sind, wurden ihre jeweiligen Vorteile in der Literatur nicht miteinander verbunden, um so eine Verbesserung ähnlicher Studien zu erreichen. Die vorliegende Studie überprüft erneut die Modellierungsstrategie, angepasst an die Simulation von Flachwasser-Karbonat-Systemen und basierend auf einer engen Beziehung zwischen Sedimentologie und Modellierung. Die vorliegende Arbeit behandelt erstmals die Evaluierung der drei am häufigsten verwendeten Algorithmen „Truncated Gaussian Simulation (TGSim)“, „Sequential Indicator Simulation (SISim)“ und „Indicator Kriging (IK)“, um sie visuell und quantitativ mit dem entsprechenden Aufschluss zu vergleichen. Die Ergebnisse zeigen, dass die Heterogenität von Karbonatgesteinen nicht komplett mit nur einem Algorithmus simuliert werden kann. Die Eigenschaften jedes einzelnen Algorithmus beinhalten Vor- und Nachteile, sodass kein Algorithmus alle Beobachtungen aus dem Aufschluss widerspiegelt. Die zwei Endglieder im Spektrum der Ablagerungsbedingungen von Karbonaten, eine flachwinklige, jurassische Karbonat-Rampe (Hoher Atlas, Marokko) und eine isolierte, triassische Plattform (Dolomiten, Italien), wurden untersucht, um einen kompletten Überblick über die verschiedenen Heterogenitäten in Flachwasser-Karbonat- Systemen zu erhalten. Sedimentologische und statistische Analysen wurden für die verschiedenen Typen, Morphologien, Verteilungen und Assoziationen von Karbonatablagerungen durchgeführt und mit paläogeografischen Rekonstruktionen kombiniert und zeigen ähnliche Ergebnisse. Im Beckenmaßstab zeigen die Faziesassoziationen, bestehend aus Fazieszonen mit ähnlichen Ablagerungsbedingungen, einen linearen und kontinuierlichen Übergang zwischen den einzelnen Ablagerungsbereichen. Im Gegensatz dazu zeigt für einzelne Lithofaziestypen im Maßstab einzelner Schichten eine mosaikartige Verteilung, bestehend aus einer Anordnung räumlich unabhängiger Lithofazieszonen entlang des Ablagerungsprofils. Das Ansteigen der räumlichen Unordnung von der beckenweiten Ablagerung zur Ablagerung einzelner Schichten resultiert aus dem Einfluss autozyklischer Faktoren bei der Ablagerung von Karbonaten. Die Skalenabhängigkeit von Karbonat-Heterogenität ist mit der Auswertung der Algorithmen verknüpft um eine Modellierungsstrategie zu etablieren, welche sowohl die sedimentären Charakteristiken des Aufschlusses als auch die Modellierfähigkeit berücksichtigt. Für die Modellierung der Ablagerungssequenzen wurde ein flächenbasierter Ansatz verwendet. Die Faziesassoziationen wurden durch die Benutzung des TGSim-Algorithmus simuliert, um die regulären Trends zwischen den einzelnen Ablagerungsgebieten zu erhalten. Im Bereich der verschiedenen Lithofazien wurde mit dem SISim-Algorithmus, ein voll stochastischer Ansatz angewendet, um die mosaikartige Verteilung der Lithofazies-Typen zu simulieren. Dieser neue Arbeitsablauf wurde konzipiert, um die Simulierung von Karbonaten auf Basis der einzelnen Heterogenitäten in verschiedenen Größenordnungen zu verbessern. Im Gegensatz zu den in der Literatur angewendeten Simulationsmethoden berücksichtigt diese Studie, dass eine einzelne Modellierungstechnik die natürlichen Ablagerungsmuster und Variabilität von Karbonaten wahrscheinlich nicht korrekt abbildet. Die Einführung verschiedener Techniken, angepasst auf die verschiedenen Ebenen der stratigrafischen Hierarchie, liefert die notwendige Flexibilität um Karbonatsysteme korrekt zu modellieren. Eine enge Verknüpfung zwischen den Fortschritten auf dem Gebieten der Sedimentologie und dem Gebiet der modellierenden Geowissenschaften sollte weiterhin bestehen, um auch zukünftig bei der Simulation von geologischen Gelände-Aufschlüssen eine Verbesserung der 3-D-Modellierung zu erreichen.
2

Magma-Carbonate Interaction and CO2 Release: A Case Study from Carlingford Igneous Centre, Ireland / Magma-karbonat-interaktion och CO2-utsläpp: En studie från Carlingford Igneous Centre, Irland

Lagrosen, Emelie January 2020 (has links)
Magma which intrudes into carbonate rich crust, interacts with the carbonate in several ways, for example by contact metamorphism and formation of marble or by metasomatism resulting in calc-silicate skarn. These processes release volatiles, such as CO2, from the carbonate and might thus cause climate change. One volcanic complex where the intrusions and their surrounding metamorphic aureole are well exposed and therefore convenient for investigation of magma-carbonate interaction is the Carlingford Igneous Centre in NE of Ireland. The complex is dominated by a gabbro lopolith and a microgranite ring dyke, which intruded into limestone and meta-siltstone at around 62-60 Ma. The purpose of this study is to investigate the extent of magma-carbonate interaction and assess the amount of CO2 which could have been released from the aureole at Carlingford. This is done by analysing major and trace elements as well as carbon and sulphur content in skarn and marble samples from a transect along the calc-silicate metamorphic aureole. The analytical methods used are SEM- EDX, XRF, LA-ICP-MS and carbon and sulphur analyses. The CO2 release is calculated by comparing the carbon and CO2 content in the skarn and marble samples with that in the unmetamorphosed limestone. The results show that the skarn has experienced a strong interaction with the magma, as it contains several high-grade minerals, such as wollastonite, vesuvianite and pyrope, and has lost almost all its carbon. The extent of interaction and amount of CO2 release is generally much lower in the marble, even though a few marble samples show a strong interaction and a high degree of degassing. On the other hand, the amount of marble in the aureole turns out to be significantly higher than the amount of skarn (70-90% compared to 10-30%). The total mass of CO2 release from the calc-silicate aureole is calculated to 0.64-9.06 Gt, where 1.30-2.67 Gt being the most realistic amount. This released CO2 has probably not caused any significant climate change on its own but may have had a small contribution to global warming together with other volcanoes that were active during the same period of time. / Magma som tränger in i karbonatrik jordskorpa, integrerar med karbonaten på flera olika sätt, t.ex. genom kontaktmetamorfos och bildande av marmor eller genom metasomatos, vilket resulterar i kalk-silikatisk skarn. Dessa processer släpper ut flyktiga ämnen, som exempelvis CO2, från karbonaten och kan därmed orsaka klimatförändring. Ett vulkaniskt komplex där intrusioner och deras omgivande metamorfa aureoler är välexponerade och därmed lämpliga för undersökning av magma-karbonat-interaktion är Carlingford Igneous Centre i nordöstra Irland. Komplexet domineras av en gabbro-lopolit och en mikrogranitisk ring-gång, som trängde in i kalksten och metasiltsten för ca 62-60 Ma. Syftet med studien är att undersöka graden av magma-karbonat-interaktion och bedöma mängden CO2 som kan ha släppts ut från aureolen i Carlingford. Detta utförs genom analysering av huvudelement och spårelement samt av kol- och svavelinnehåll i skarn- och marmorprover från en transekt genom den kalk-silikatiska metamorfa aureolen. De analytiska metoder som används är SEM-EDX, XRF, LA-ICP- MS samt kol- och svavelanalyser. Mängden CO2 beräknas genom att jämföra kol- och CO2-innehåll i skarn- och marmorprover med innehållet kol och CO2 i den ickemetamorfa kalkstenen. Resultaten visar att skarn har genomgått en stark interaktion med magman, då bergarten innehåller flera mineral av hög metamorf grad, som exempelvis wollastonit, vesuvianit och pyrop, samt har förlorat nästan allt sitt kol. Graden interaktion och mängden CO2-utsläpp är generellt mycket lägre i marmorn än i skarnen, även fast några marmorprover visar stark interaktion och en stor del avgasning. Å andra sidan är mängden marmor i aureolen signifikant högre än mängden skarn (70-90% jämfört med 10-30%). Den totala massan av CO2-utsläpp från den kalk-silikatiska delen av aureolen är beräknad till 0,64-9,06 Gt, där 1,30-2,67 Gt anses vara den mest realistiska mängden. Detta utsläpp av CO2 har troligtvis inte orsakat någon signifikant klimatpåverkan på egen hand, men kan ha haft en liten bidragande effekt till global uppvärmning tillsammans med andra vulkaner som var aktiva under samma geologiska tidsperiod.
3

Geochemical and isotope investigations of carbonate sinter – 2000 years of water supply management in Palestine

Sabri, Raghid N. R. 12 December 2016 (has links) (PDF)
Over thousands of years, the eastern part of the Mediterranean has developed ways to supply and manage its water resources. The most important evidence of this is the water networks that are distributed in the area. Case studies involving a literature review, fieldwork, sample collection and analysis were conducted that focused on two areas in the West Bank: Nablus city and the northern part of Jordan Valley. These locations were chosen because Nablus city and its vicinity have many of Roman tunnels and aqueducts while the Jordan Valley has many watermills. This study aims to examine the changes in water quality over time in various ways; in an attempt to explain environmental degradation, to understand archeological aspects relating to the water management system, and to piece together what sustained the past environmental development. Throughout centuries carbonate deposits have accumulated along the sidewalls of the water system, containing and archiving geochemical and hydraulic information. These carbonate deposits were sampled from the walls of tunnels together with water samples from the tunnel and surrounding springs in the area. In addition, carbonate sinter has accumulated at the outlet of the watermill on the water shaft. This sinter was also sampled along with water samples from the springs and the water in the Wadi in the area. Water and carbonate samples were analyzed. Water analysis included major cations and anions, trace elements, rare earth elements, 18O/16O isotope ratio, and 87Sr/86Sr isotope ratio. Results indicate the presence of different underground water bodies and Sr resources. Furthermore, thin sections were made from the carbonate samples for SEM–EDX analyses and microscopic investigations. The microscope analysis showed that the distribution of minerals precipitated differs within one sample. Likewise, SEM–EDX results show a variation in element distribution along the growth axis. After finishing the analysis of water samples and thin sections, the layers of the carbonate samples were acidified and trace elements and rare earth elements were measured by means of ICP–MS. Then selected layers were prepared for isotope analyses (18O, 13C, and 87Sr/86Sr) and subsequently measured. The carbonate samples were dated using the U–Th method. Rare earth elements and trace elements measurements provide clear evidence that urbanization has an adverse effect on groundwater quality. Different groundwater bodies were identified by means of geochemical analysis. In the same way, the water sources used to feed the ancient water system were also identified. Through petrological and geochemical analysis, the sustainability of the watermill concept could be demonstrated. This study recommends a more controlled regulation of urbanization expansion. It will only be possible to continue living in this region with sufficient amounts of groundwater and innovative techniques for water supply and management that are environmentally sustainable, as it used to be centuries ago.
4

Single-Step Covalent Functionalization of Polylactide Surfaces / Nano Patterened Covalent Surface Modification of Poly(ε-caprolactone)

Källrot, Martina January 2005 (has links)
<p>Degradable polymers have gained an increased attention in the field of biomedical applications over the past decades, for example in tissue engineering. One way of improving the biocompatibility of these polymers is by chemical surface modification, however the risk of degradation during the modification procedure is a limiting factor. In some biomedical applications, for example in nerve guides, a patterned surface is desired to improve the cell attachment and proliferation.</p><p>In this thesis a new non-destructive, single-step, and solvent free method for surface modification of degradable polymers is described. Poly(L-lactide) (PLLA) substrates have been functionalized with one of the following vinyl monomers; N-vinylpyrrolidone (VP), acrylamide (AAm), or maleic anhydride (MAH) grafts. The substrates were subjected to a vapor phase atmosphere constituted of a mixture of a vinyl monomer and a photoinitiator (benzophenone) in a closed chamber at very low pressure and under UV irradiation. Poly(ε-caprolactone) (PCL), poly(lactide-co-glycolide) (PLGA), and poly(trimethylene carbonate) (PTMC) have been surface modified with VP using the same procedure to show the versatility of the method. The wettability of all of the four substrates increased after grafting. The surface compositions were confirmed by ATR-FTIR and XPS. The VP grafted PLLA, PTMC and PLGA substrates have been shown to be good substrates for the normal human cells i.e. keratinocytes and fibroblasts, to adhere and proliferate on. The topography of substrates with well defined nano patterns was preserved during grafting, since the grafted layer is very thin. We have also shown that the method is useful for a simultaneous chemical and topographical modification of substrates by masked vapor phase grafting. The surface topography was determined with SEM and AFM.</p> / <p>Intresset för användningen av nedbrytbara polymerer till biomedicinska applikationer som till exempel vävnads rekonstruktion har ökat avsevärt de senaste decennierna. Ett sätt att öka biokompatibiliteten hos dessa polymerer är genom kemisk ytmodifiering, men risken för nedbrytning under själva modifieringen är en begränsande faktor. I vissa biomedicinska applikationer, till exempel nervguider, är det önskvärt att ha en väldefinierad ytstruktur för att öka vidhäftningen och tillväxten av celler.</p><p>I den här avhandlingen presenteras en ny ickeförstörande, lösningsmedelsfri enstegsprocess för ytmodifiering av nedbrytbara polymerer. Substrat av poly(L-laktid) (PLLA) har ytfunktionaliserats med var och en av följande vinylmonomerer, N-vinylpyrrolidon (VP), akrylamid (AAm) eller maleinsyraanhydrid (MAH). Substraten har exponerats för en gasfasatmosfär av en blandning av en vinylmonomer och en fotoinitiator (bensofenon) i en tillsluten reaktor vid mycket lågt tryck och under UV-strålning. Metodens mångsidighet har även påvisats genom att ytmodifiera substrat av poly(ε-kaprolakton) (PCL), poly(laktid-co-glykolid) (PLGA) och poly(trimetylen karbonat) (PTMC) med VP. Vätbarheten ökade för alla fyra materialen efter ympning med en vinylmonomer. Ytsammansättningen fastställdes med ATR-FTIR och XPS. De VP ympade filmerna av PLLA, PLGA och PTMC visade sig vara bra substrat för mänskliga celler, i detta fall keratinocyter och fibroblaster, att vidhäfta och växa på. Yttopografin hos filmer med väldefinierade nanomönstrade ytor kunde bevaras efter ympning, tack vare att det ympade lagret är så tunt. Gasfas metoden har också visat sig användbar för att simultant ytmodifiera både kemiskt och topografiskt genom maskad gasfasympning. Yttopografin bestämdes med SEM och AFM.</p>
5

Geochemical and isotope investigations of carbonate sinter – 2000 years of water supply management in Palestine

Sabri, Raghid N. R. 04 November 2016 (has links)
Over thousands of years, the eastern part of the Mediterranean has developed ways to supply and manage its water resources. The most important evidence of this is the water networks that are distributed in the area. Case studies involving a literature review, fieldwork, sample collection and analysis were conducted that focused on two areas in the West Bank: Nablus city and the northern part of Jordan Valley. These locations were chosen because Nablus city and its vicinity have many of Roman tunnels and aqueducts while the Jordan Valley has many watermills. This study aims to examine the changes in water quality over time in various ways; in an attempt to explain environmental degradation, to understand archeological aspects relating to the water management system, and to piece together what sustained the past environmental development. Throughout centuries carbonate deposits have accumulated along the sidewalls of the water system, containing and archiving geochemical and hydraulic information. These carbonate deposits were sampled from the walls of tunnels together with water samples from the tunnel and surrounding springs in the area. In addition, carbonate sinter has accumulated at the outlet of the watermill on the water shaft. This sinter was also sampled along with water samples from the springs and the water in the Wadi in the area. Water and carbonate samples were analyzed. Water analysis included major cations and anions, trace elements, rare earth elements, 18O/16O isotope ratio, and 87Sr/86Sr isotope ratio. Results indicate the presence of different underground water bodies and Sr resources. Furthermore, thin sections were made from the carbonate samples for SEM–EDX analyses and microscopic investigations. The microscope analysis showed that the distribution of minerals precipitated differs within one sample. Likewise, SEM–EDX results show a variation in element distribution along the growth axis. After finishing the analysis of water samples and thin sections, the layers of the carbonate samples were acidified and trace elements and rare earth elements were measured by means of ICP–MS. Then selected layers were prepared for isotope analyses (18O, 13C, and 87Sr/86Sr) and subsequently measured. The carbonate samples were dated using the U–Th method. Rare earth elements and trace elements measurements provide clear evidence that urbanization has an adverse effect on groundwater quality. Different groundwater bodies were identified by means of geochemical analysis. In the same way, the water sources used to feed the ancient water system were also identified. Through petrological and geochemical analysis, the sustainability of the watermill concept could be demonstrated. This study recommends a more controlled regulation of urbanization expansion. It will only be possible to continue living in this region with sufficient amounts of groundwater and innovative techniques for water supply and management that are environmentally sustainable, as it used to be centuries ago.:Declaration V Acknowledgment VI Abstract VIII List of Figures X List of Tables XVI List of Abbreviations XVII Terms and definitions XIX 1. Introduction 1 1.1 Structure of the thesis 1 1.2 General information, background 2 1.2.1 Spiritual value of water in Palestine 2 1.2.2 Water resources and management condition in Palestine 3 1.2.3 Water crisis in Palestine 4 1.3 Motivation 5 1.4 Hypothesis 6 1.5 Location of study area 6 1.5.1 Description of geology and hydrogeology of the study area 8 1.5.2 Climate 13 2. Literature review 18 2.1 Research history of aqueducts 18 2.2 Aqueducts in Palestine 18 2.2.1 Agricultural aqueducts (related to watermills) in Palestine 20 2.3 Utilization of springs in Palestine 21 2.3.1 Ancient water system in Nablus–Sebestia 22 2.4 Carbonate sinter accumulation in aqueducts and artificial water network 24 2.4.1 Research history of secondary carbonate sinter 26 2.4.2 Growth mechanism of secondary carbonate 29 2.4.3 Carbonate sinter analysis 30 3. Methodology 33 3.1 Literature review 33 3.2 Fieldwork 34 3.3 Sampling and analysis 37 3.3.1 Water samples: 37 3.3.2 Carbonate samples 38 3.3.3 U–Th series dating 41 3.4 Software used 43 3.5 Challenges 43 4. Results and discussion (Nablus area) 45 4.1 Ancient water system description 45 4.2 Water sample results and discussion 54 4.2.1 Stable isotope 59 4.2.2 Strontium isotope analysis (87Sr/86Sr) 60 4.2.3 Saturation index 62 4.2.4 Discussion 63 4.3 Carbonate analysis (host rock) 64 4.4 Aqueduct building material 65 4.5 Secondary carbonate analysis 66 4.5.1 Ras Al Ein location (S-2) 66 4.5.2 Ijnisinya location (S-9) 72 4.5.3 Harun Location (S-8) 79 4.5.4 Water tunnel Location (A-1) 86 4.5.5 Water aqueduct Location (A-4) 99 4.6 Discussion 101 4.6.1 Is urbanization a source of groundwater quality degradation? 101 4.6.3 Paleoclimate calculations 105 5. Results and discussion (Al Malih area) 107 5.1 Water system description 107 5.2 Geochemical results (water) 108 5.3 Geochemical results (Carbonate) 111 5.3 Sustainability of watermills 113 6. Conclusions and recommendation 115 6.1 Conclusions 115 6.2 Recommendations 116 6.2.1 Recommendation for further research 116 6.2.2 Recommendation for policy makers 116 References 118
6

Covalent Surface Modification of Degradable Polymers for Increased Biocompatibility / Nano Patterened Covalent Surface Modification of Poly(ε-caprolactone)

Källrot, Martina January 2005 (has links)
Degradable polymers have gained an increased attention in the field of biomedical applications over the past decades, for example in tissue engineering. One way of improving the biocompatibility of these polymers is by chemical surface modification, however the risk of degradation during the modification procedure is a limiting factor. In some biomedical applications, for example in nerve guides, a patterned surface is desired to improve the cell attachment and proliferation. In this thesis a new non-destructive, single-step, and solvent free method for surface modification of degradable polymers is described. Poly(L-lactide) (PLLA) substrates have been functionalized with one of the following vinyl monomers; N-vinylpyrrolidone (VP), acrylamide (AAm), or maleic anhydride (MAH) grafts. The substrates were subjected to a vapor phase atmosphere constituted of a mixture of a vinyl monomer and a photoinitiator (benzophenone) in a closed chamber at very low pressure and under UV irradiation. Poly(ε-caprolactone) (PCL), poly(lactide-co-glycolide) (PLGA), and poly(trimethylene carbonate) (PTMC) have been surface modified with VP using the same procedure to show the versatility of the method. The wettability of all of the four substrates increased after grafting. The surface compositions were confirmed by ATR-FTIR and XPS. The VP grafted PLLA, PTMC and PLGA substrates have been shown to be good substrates for the normal human cells i.e. keratinocytes and fibroblasts, to adhere and proliferate on. The topography of substrates with well defined nano patterns was preserved during grafting, since the grafted layer is very thin. We have also shown that the method is useful for a simultaneous chemical and topographical modification of substrates by masked vapor phase grafting. The surface topography was determined with SEM and AFM. / Intresset för användningen av nedbrytbara polymerer till biomedicinska applikationer som till exempel vävnads rekonstruktion har ökat avsevärt de senaste decennierna. Ett sätt att öka biokompatibiliteten hos dessa polymerer är genom kemisk ytmodifiering, men risken för nedbrytning under själva modifieringen är en begränsande faktor. I vissa biomedicinska applikationer, till exempel nervguider, är det önskvärt att ha en väldefinierad ytstruktur för att öka vidhäftningen och tillväxten av celler. I den här avhandlingen presenteras en ny ickeförstörande, lösningsmedelsfri enstegsprocess för ytmodifiering av nedbrytbara polymerer. Substrat av poly(L-laktid) (PLLA) har ytfunktionaliserats med var och en av följande vinylmonomerer, N-vinylpyrrolidon (VP), akrylamid (AAm) eller maleinsyraanhydrid (MAH). Substraten har exponerats för en gasfasatmosfär av en blandning av en vinylmonomer och en fotoinitiator (bensofenon) i en tillsluten reaktor vid mycket lågt tryck och under UV-strålning. Metodens mångsidighet har även påvisats genom att ytmodifiera substrat av poly(ε-kaprolakton) (PCL), poly(laktid-co-glykolid) (PLGA) och poly(trimetylen karbonat) (PTMC) med VP. Vätbarheten ökade för alla fyra materialen efter ympning med en vinylmonomer. Ytsammansättningen fastställdes med ATR-FTIR och XPS. De VP ympade filmerna av PLLA, PLGA och PTMC visade sig vara bra substrat för mänskliga celler, i detta fall keratinocyter och fibroblaster, att vidhäfta och växa på. Yttopografin hos filmer med väldefinierade nanomönstrade ytor kunde bevaras efter ympning, tack vare att det ympade lagret är så tunt. Gasfas metoden har också visat sig användbar för att simultant ytmodifiera både kemiskt och topografiskt genom maskad gasfasympning. Yttopografin bestämdes med SEM och AFM. / QC 20101014

Page generated in 0.4285 seconds