Dissertations / Theses on the topic 'Silicone hydrogel'
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Rutschilling, Ryan R. "Evaluation of Wear Experience with Silicone Hydrogel Lenses in Current Silicone Hydrogel Planned Replacement Lens Wearers." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1618559832574561.
Full textRubido, Jacinto S. "Ocular response to silicone-hydrogel contact lenses." Thesis, Aston University, 2004. http://publications.aston.ac.uk/14538/.
Full textTam, Ngai Keung. "Comfort and Compatibility of Silicone Hydrogel Contact Lenses." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4031.
Full textNagapatnam, Subbaraman Lakshman. "Lysozyme Deposition Studies on Silicone Hydrogel Contact Lens Materials." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1245.
Full textSzczotka-Flynn, Loretta B. "The Longitudinal Analysis of Silicone Hydrogel Contact Lens Study." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1257182345.
Full textSchafer, Jeffrey M. "A characterization of dryness symptoms with Silicone Hydrogel contact lenses." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1407508203.
Full textLorentz, Holly. "Lipid Deposition on Hydrogel Contact Lenses." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2963.
Full textHarp, Lisa. "Contributions of Silicone Hydrogel Transmissibility and Tear Exchange to Corneal Oxygen Supply." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275496222.
Full textZhao, Yibei. "Phospholipid Transport in Silicon Hydrogel Contact Lenses." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3083.
Full textLewis, Kristen Oblad. "COMPARATIVE LIPIDOMICS OF HYDROGEL CONTACT LENSES IN-VITRO AND IN-VIVO." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243889772.
Full textAshleigh, Claudia. "A double masked randomised crossover trial of two silicone hydrogel multifocal contact lenses." Thesis, London South Bank University, 2017. http://researchopen.lsbu.ac.uk/1988/.
Full textRogers, Ronan. "In vitro and ex vivo wettability of hydrogel contact lenses." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2974.
Full textThere are many ways to assess the wettability of a given material, namely sessile drop,1 captive bubble 2 or Wilhelmy plate. 3 This thesis used the sessile drop method to determine the surface wettability of various hydrogel contact lens materials, by measuring the advancing contact angle made between the lens surface and a pre-determined volume of HPLC-grade water. This was followed by measuring the surface wettability following periods in which the lens materials were soaked in various contact lens care regimens. Further studies determined wettability of lens materials after various periods of in-eye wear and finally a study was undertaken to evaluate if a novel biological technique could be used to differentiate proteins that deposit on hydrogel lens materials that may affect wettability and cause discomfort.
A variety of hydrogel lenses, taken directly from their packaging and after soaking in various care regimens, were analyzed to determine their sessile drop advancing contact angles, in vitro. These studies indicated that poly-2-hydroxyethylmethacrylate (pHEMA)-based lenses are inherently more wettable than silicone-based lenses, unless they have a surface treatment that completely covers the hydrophobic siloxane groups. Additionally, certain combinations of lens materials and care regimens produce inherently more wettable surfaces when measured in vitro.
Suitable methods to assess contact lens wettability ex vivo, or after subjects had worn lenses for set periods of time, were developed. It was determined that using latex gloves to remove lenses had no impact upon the lens surface wettability and that rinsing of the lens surface after removal from the eye was required to determine the wettability of the underlying polymer.
The final wettability studies involved an analysis of various lens materials from clinical studies conducted within the Centre for Contact Lens Research (CCLR). These studies investigated differences in wettability between silicone hydrogel lenses manufactured from differing polymers and variations in ex vivo wettability of several combinations of lens materials and solutions, worn for varying periods of time.
A novel method to investigate proteins extracted from lenses using 2D-Difference in Gel Electrophoresis (DIGE) found that this technique could be used to analyze proteins extracted from contact lenses. The data obtained showed that there was no difference between a group of subjects who were symptomatic of lens-induced dryness or a control group, and that care solutions had a minimal influence on the pattern of deposition seen.
The overall conclusion of these studies is that hydrogel lens wettability is affected by the polymer composition and that care regimen components can modify the surface wettability.
Tagliaferri, Angela. "Risk Factors for Contact Lens Induced Papillary Conjunctivitis Associated with Silicone Hydrogel Contact Lens Wear." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1339094018.
Full textRead, Michael Leonard. "The impact of material surface characteristics on the clinical wetting properties of silicone hydrogel contact lenses." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/the-impact-of-material-surface-characteristics-on-the-wetting-properties-of-silicone-hydrogel-contact-lenses(f9052c88-3fe8-4467-8cda-7feb5b63c066).html.
Full textHermies, François d'. "Etudes experimentale chez le lapin et clinique chez l'homme des biomateriaux d'indentation." Nancy 1, 2000. http://www.theses.fr/2000NAN11313.
Full textKeay, Lisa Jane Optometry & Vision Science Faculty of Science UNSW. "Public health impact of contact lens related microbial keratitis." Awarded by:University of New South Wales. School of Optometry and Vision Science, 2006. http://handle.unsw.edu.au/1959.4/26307.
Full textHorne, Ryan Ruben. "Thermal and Convective Loading Methods for Releasing Hydrophobic Therapeutics from Contact Lenses." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6388.
Full textOsborn, Tim H. "Ab Initio Simulations of Hydrogen and Lithium Adsorption on Silicene." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1283177822.
Full textKim, Hyoun-Ee. "Gaseous corrosion of silicon carbide and silicon nitride in hydrogen /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487327695622538.
Full textHuy. "Hydrogen interaction with impurities in silicon." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2001. http://dare.uva.nl/document/59764.
Full textGhita, M. "Hydrogen diffusion and trapping in crystalline silicon." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517282.
Full textStübner, Ronald. "Electrical characterization of carbon-hydrogen complexes in silicon and silicon-germanium alloys." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233055.
Full textIn dieser Arbeit werden die elektrischen Eigenschaften von Kohlenstoff-Wasserstoff-Komplexen in Silizium (Si) und Silizium-Germanium-Legierungen (SiGe) studiert. Diese Komplexe bilden sich durch Reaktion von Kohlenstoff-Verunreinigungen mit Wasserstoff, welcher durch nasschemisches Ätzen oder eine Wasserstoffplasma-Behandlung eingebracht wird. Der Nachweis und die Charakterisierung der Defekte erfolgte mit den Methoden der Kapazitätstransientenspektroskopie (DLTS), Laplace DLTS und der Minoritätsladungsträgertransientenspektroskopie (MCTS). Damit wurden Eigenschaften wie die Aktivierungsenergie der Ladungsträgeremission, die Einfangquerschnitte, der Ladungszustand und die thermische Stabilität der Komplexe bestimmt. Die Zusammensetzung der Komplexe wurde durch eine Analyse der Tiefenprofile ermittelt, welche in Proben mit verschiedenen Verunreinigungskonzentrationen gemessen wurden. Mit diesen Methoden wurde acht Kohlenstoff-Wasserstoff-korrelierte Defektniveaus (E42, E65, E75, E90', E90, E262, H50, H180) in Si und SiGe und ein Wasserstoff-korreliertes Niveau in Ge nachgewiesen. Eine Wasserstoffplasma-Behandlung bei Temperaturen um 373 K erzeugt vier dominante Defektniveaus in Si bei Ec-0.06 eV (E42), Ec-0.52 eV (E262), Ev+0.33 eV (H180) und Ev+0.08 eV. Es wird gezeigt, dass E42 und E262 zwei Ladungszustände desselben Defektes sind. Die charakteristische Feldabhängigkeit der Emissionsrate zeigt, dass E42 der Doppel-Akzeptor- und E262 der Einfach-Akzeptor-Zustand eines CH-Komplexes ist. Durch Vergleich der beobachteten Eigenschaften mit theoretischen Berechnungen werden beide Niveaus der antibindenden Konfiguration des CH-Komplexes (CH_1AB) zugeordnet. Das Niveau H180 wurde in der Literatur bisher mit dem Donator-Zustand der CH_1AB-Konfiguration in Verbindung gebracht. Diese Hypothese konnte nicht bestätigt werden. Es wird gezeigt, dass H180 eine Barriere für den Löchereinfang von etwa 53 meV besitzt, was die Bestimmung des Ladungszustandes aus der Feldabhängigkeit der Emissionsrate erschwert. Die Aktivierungsenergie von H180 stimmt jedoch befriedigend mit der berechneten Aktivierungsenergie des Akzeptorzustandes der CH_T-Konfiguration überein, bei der H auf der T-Zwischengitterposition sitzt. Daher wird H180 vorläufig dem CH_T-Komplex zugeordnet. Das Niveau H50, welches zum ersten Mal hier beschrieben wird, wird nur mit sehr geringen Konzentrationen nachgewiesen. Dies erschwert die Bestimmung des Ladungszustandes. Die Aktivierungsenergie von H50 stimmt jedoch auffallend gut mit dem von der Theorie vorhergesagten Akzeptorniveau von CH_2AB (Ev+0.07 eV) überein. Daher wird H50 vorrübergehend CH_2AB zugeordnet. Das Einbringen von Wasserstoff in Silizium durch nasschemisches Ätzen führt zu drei dominanten Defektniveaus bei Ec-0.11 eV (E65), Ec-0.13 eV (E75) und Ec-0.16 eV (E90). E90 wurde bisher widersprüchlich von verschiedenen Autoren dem Donatorzustand und dem Akzeptorzustand der bindungszentrierten Konfiguration (CH_1BC) des CH-Komplexes zugeordnet. Dieser Widerspruch konnte aufgelöst werden. Es wird gezeigt, dass in Silizium mit niedrigem Sauerstoffanteil (< 1E17 cm^-3) zwei verschiedene Defektniveaus (E90 und E90') bei etwa 90 K in den DLTS-Spektren erscheinen, welche nur mit der Laplace DLTS-Technik aufgelöst werden können. Der Akzeptorzustand der CH_1BC-Konfiguration kann direkt nach nasschemischem Ätzen oder einer Wasserstoffplasma-Behandlung bei 373 K beobachtet werden. Im Gegensatz dazu wird durch eine Sperrspannungs-Temperung in Proben mit einer Donatorkonzentration von Nd > 1E15 cm^-3 der Donatorzustand eines CH_n-Komplexes (E90', Ec-0.14 eV), welcher mehr als ein Wasserstoffatom enthält, gebildet. Durch Vergleich mit theoretischen Berechnungen wird n > 2 geschlussfolgert. Die Niveaus E65 und E75 sind in Proben mit einem hohen Sauerstoffanteil (> 1E17 cm^-3) dominant. Beide Niveaus gehören zu einer durch ein O-Atom verzerrten CH_1BC-Konfiguration. Das Auftreten von zwei Niveaus wird durch zwei nicht-äquivalente Positionen des O-Atoms bezüglich der CH-Bindung erklärt. Die Eigenschaften von E42, E90, E262 und H180 wurden ebenfalls in verdünnten SiGe-Legierungen untersucht. Es wird gezeigt, dass Ge-Atome in der direkten Umgebung der Defekte zusätzliche Defektniveaus erzeugen, die in der Bandlücke nahe zu den Si-Defektniveaus liegen und von durch Ge-Atomen verzerrten Defekten stammen. Die beobachteten relativen Konzentrationen dieser Ge-korrelierten Niveaus kann mit Modellen der atomaren Struktur der Defekte erklärt werden. Eine Verschiebung der Defektniveaus proportional zum Ge-Anteil in der Legierung wurde beobachtet. Eine Extrapolation dieser Verschiebung legt den Schluss nahe, dass E90 und E262 auch in reinem Ge beobachtbar sein sollten. Tatsächlich wurde ein Wasserstoff-korrelierter Defekt E150 (Ec-0.31 eV) in n-Typ Germanium beobachtet. Die Konzentration von E150 ist nach einer Wasserstoffplasma-Behandlung wesentlich höher als nach nasschemischen Ätzen. Es wird gezeigt, dass E150 ein einzelnes Wasserstoffatom und ein noch unbekanntes Verunreinigungsatom enthält, höchstwahrscheinlich Kohlenstoff, Sauerstoff oder Silizium. Damit ist E150 ein sehr wahrscheinlicher Kandidat für einen CH-Komplex in Germanium
Burrows, Michael Z. "Role of silicon hydride bonding environment in alpha-silicon hydrogen films for c-silicon surface passivation /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 152 p, 2008. http://proquest.umi.com/pqdweb?did=1654501711&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textO'Connell, Jacques Herman. "Characterization of hydrogen and helium implanted silicon carbide." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/979.
Full textJanson, Martin. "Hydrogen diffusion and ion implantation in silicon carbide." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3482.
Full textSecondary ion mass spectrometry (SIMS) has been employed tostudy the spatial distributions resulting from mass transportby diffusion and ion implantation in single crystal siliconcarbide (SiC). By a systematic analysis of this data,fundamental processes that govern these phenomena have beenderived.
The acceptor atoms Al and B are known to be electricallypassivated by H in SiC. By studying the thermally stimulatedredistribution of implanted deuterium (2H) in various acceptordoped structures, it is found that hydrogen forms complexeswith the doping atoms, and also interacts strongly withimplantation induced defects. A comprehensive understanding ofthe formation and dissociation kinetics of these complexes hasbeen obtained. The extracted effective capture radius for theformation of 2H-B complexes is in good agreement with thatexpected for a coulomb force assisted trapping mechanism. Thelarge difference of 0.9 eV in the extracted dissociationenergies for the 2H-Al and 2H-B complexes suggests that theatomic configurations of the two complexes are significantlydifferent. Furthermore, by studying the migration behavior of Hin the presence of built-in electric fields, it is concludedthat all of the mobile H is in the positive charge state inp-type SiC.
A large number of implantations have been performed withrespect to ion mass, energy, fluence, and crystal orientation.The electronic stopping cross sections in the low velocityregime for ions with atomic numbers 1 ≤ Z1 ≤ 15have been extracted from the ion range distributions. Theydisplay both Z1-oscillations and a smaller than velocityproportional stopping for ions with Z1 ≤ 8, in agreementwith previous reports for other materials. Furthermore, thedegree of ion channeling in various major axial and planarchannels of the 6H and 4H-SiC crystal has been explored. Twotypes of ion implantation simulators have been developed. Onebased on a statistical, data-base approach, and one atomisticsimulator, based on the binary collision approximation (BCA).By fitting BCA simulated profiles to the experimental profiles,detailed information about the electronic stopping andimplantation induced damage is extracted. In addition, thevacancy-related damage caused by the implantations has beeninvestigated by positron annihilation spectroscopy (PAS). Twotypes of implantation induced positron traps have been isolatedand are tentatively identified as a Si vacancy (VSi) and a Si-Cdivacancy (VSiVC). The extension of detected VSi is in goodagreement with that predicted by BCA simulations, and forimplantations with heavier ions VSi are revealed at far greaterdepths than the mean projected ion range due to deeplypenetrating channeled ions.
Bowyer, Ellis T. "Electrical detection of hydrogen-like donors in silicon." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616937.
Full textWilkinson, Andrew Richard. "The optical properties of silicon nanocrystals and the role of hydrogen passivation /." View thesis entry in Australian Digital Program, 2006. http://thesis.anu.edu.au/public/adt-ANU20060202.111537/index.html.
Full textYin, Chengying. "Hydrogen production from irradiated calcium silicate hydrate." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS355/document.
Full textIn France, cementitious materials are used as conditioning matrix of low level and intermediate level nuclear wastes. Water radiolysis occurs due to the nuclear wastes stored in the materials. The formation of its radiolytic products such as H₂ gas must be evaluated for safety reasons. Calcium silicate hydrate (C-S-H) is the main product (50%) of hydration of Portland Cement (PC). The aim of this study is to understand the radiolytic mechanisms of the hydrogen production in C-S-H, to investigate the effect of impurities (such as alkali ions, additional hydroxides or nitrates ions) on H₂ gas production in C-S-H and to examine if interactions exist between different main phases (C-S-H and portlandite) in cement matrix. After using various characterization techniques, samples were submitted to different types of irradiation (gamma rays and electrons and heavy ions (HI) beams) to determine their H₂ radiolytic yield, G(H₂). In C-S-H system, it has been shown, under gamma irradiation, that G(H₂) does not depend on water content, moreover, C-S-H system itself produce efficiently H₂ gas. The comparison between the results obtained under gamma rays and that obtained under HI implies: there is no/ low LET effect in C-S-H. While with nitrate ions in C-S-H, a large decrease of G(H₂) is observed. Irradiation of C2S and C3S hydrates mainly composed of C-S-H and portlandite shows that here is no energy transfer phenomena between these two phases. Finally, the electron paramagnetic resonance (EPR) spectroscopy experiments have enabled proposing radiolytic mechanisms. All these results help us to understand the radiation effects in cements
Luongo, Kevin. "Palladium Doped Nano Porous Silicon to Enhance Hydrogen Sensing." Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3896.
Full textBrown, Andrew Richard. "Enhanced oxygen diffusion in silicon catalysed by atomic hydrogen." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46685.
Full textTerry, Jonathan Gordon. "Electrical characterisation of transition metals and hydrogen in silicon." Thesis, University of Manchester, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680103.
Full textBîlteanu, Liviu. "Atomic scale simulation of hydrogen related defects in hydrogen implanted silicon - Smart Cut™ technology." Paris 11, 2010. http://www.theses.fr/2010PA112293.
Full textThe topic of this thesis is related to the implantation step of the Smart Cut™ technology. This technology uses hydrogen in order to transfer silicon layers on insulating substrates. The transfer is performed through a fracture induced by the formation of bidimensional defects well known in Iiterature as "platelets". More exactly, we have studied within this thesis work the defects appearing in the post implant state and the evolution of the implantation damage towards a state dominated by platelets. The study is organised into two parts: in the first part we present the results obtained by atomic scale simulations while the second part we present an infrared spectroscopy study of the evolution of defects concentrations after annealing at different temperatures. The atomic scale simulations have been performed within the density functional theory and they allowed us to compute the formation energies and the migration and recombination barriers. The defects included in our study are: the atomic and diatomic interstitials, the hydrogenated vacancies and multivacancies and the several platelets models. The obtained energies allowed us to build a stability hierarchy for these types of defects. This scheme has been confronted with some infrared analysis on hydrogen implanted silicon samples (37 keV) in a sub-dose regime which does not allow usually the formation of platelets during the implantation step. The analysis of the infrared data allowed the detailed description of the defects concentration based on the behaviour of peaks corresponding to the respective defects during annealing. The comparison between these evolutions and the energy scheme obtained previously allowed the validation of an evolution scenario of defects towards the platelet state
Wilkinson, Andrew Richard, and arw109@rsphysse anu edu au. "The Optical Properties of Silicon Nanocrystals and the Role of Hydrogen Passivation." The Australian National University. Research School of Physical Sciences and Engineering, 2006. http://thesis.anu.edu.au./public/adt-ANU20060202.111537.
Full textAbdul-Niby, Mohammed. "Photoconductive frequency resolved spectroscopy for hydrogen and helium implanted silicon." Thesis, University of Surrey, 1997. http://epubs.surrey.ac.uk/804439/.
Full textMartsinovich, Natalia. "Theory of defects arising from hydrogen in silicon and diamond." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409286.
Full textHourahine, Benjamin. "A first principles study of hydrogen related defects in silicon." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324743.
Full textSampson, Gareth Milo. "Hydrogen atom and argon ion reactions for removing hydrocarbon adsorbates and contamination from silicon surfaces /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Full textRai, Chaudhuri Anjana. "Electronic structure and bond energy trends in silicon-hydrogen and germanium-hydrogen bond activation by transition metals." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184731.
Full textTizard, Geoffrey Alexander. "Characterization of the Viscoelastic Fracture of Solvated Semi-Interpenetrating Polymer Network Silicone Hydrogels." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/34232.
Full textMaster of Science
Höchbauer, Tobias. "On the mechanisms of hydrogen implantation induced silicon surface layer cleavage." [S.l.] : [s.n.], 2001. http://archiv.ub.uni-marburg.de/diss/z2002/0403.
Full textBrown, Peter William. "Chemical vapor deposition of silicon carbide in the methyltrichlorosilane-hydrogen system /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487844485899111.
Full textHuang, Ming-Chieh. "Silicon microfabricated device for non-sheath-flow cytometer-based chemical analysis and microchannel flow sensing /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5870.
Full textYelundur, Vijay Nag. "Understanding and Implementation of Hydrogen Passivation of Defects in String Ribbon Silicon for High-Efficiency, Manufacturable, Silicon Solar Cells." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5271.
Full textFawcett, Timothy J. "Investigation into the hydrogen gas sensing mechanism of 3C-SiC resistive gas sensors." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001537.
Full textGUO, GUAN-SIAN, and 郭冠賢. "Development of Functional Silicone Hydrogel." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/hqjxav.
Full text國立聯合大學
化學工程學系碩士班
106
In our study, a sol-gel process was used to synthesize the organic-inorganic hybrid prepolymers. The prepolymers were mixed with other formulas by photo-polymerization method to obtain the high oxygen permeability and functional silicone hydrogels for the applications of soft contact lens. In addition, the effect of prepolymer’s content on the properties of the silicone hydrogels was carried out by various analysis methods. The ratio of prepolymers affects the hydrophilicity/ hydrophobicity and degree of cross-linking of hydrogels, but also influence the swelling behavior, contact angle, mechanical properties and the thermal behavior states of water of the silicone hydrogels. The results show that the hydrogels follow the Non-Fickian diffusion (Case III) model via the swelling kinetics analysis, and the mechanism exponent (n) range of the samples was from 0.5 to 1, meaning that the relaxation rate of the polymer chain was similar to the solvent diffusion rate. According to ISO10993-5 method by the vitro cytotoxicity test, the functional silicone hydrogels expressed no toxic response and has good biocompatibility. Apart from that, the formulation of hydrogels incorporated the natural health-care pigment, which expressed a good light filtering ability and prevented eye damage in the short-wavelength blue light range (381-460nm). And the blue light blocking function of natural pigment was not only better than that of commercial products, but also has the function of alleviating eye fatigue. In the eye care drug (Vitamin B12) loading release experiment, n value was about 0.5, which was close to the ideal Fick's diffusion mechanism. It illustrated that the silica hydrogels could adjust the diffusion rate by the drug concentration.
Tsai, Ming-Chan, and 蔡明展. "Preparation and hydrophilicity of ionized silicone hydrogel films." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/znk3e3.
Full text國立臺灣科技大學
材料科學與工程系
105
This study is to synthesize positively charged silicon hydrogel, so that the moisturizing agent in the preserving buffer solution can be attacted to positively charged silicon hydrogel to improve the surface wettability of contact lens. The main component of this hydrogel is hydroxyl-terminated polydimethyl siloxane (PDMS-diol), which serves as the soft segment of a polyurethane (PU) macromer. After reacting with isophorone diisocyanate (IPDI), polyethylene glycol 600 (PEG 600) was added to increase the hydrophilicity of the resultant PU. Then 2-(dimethylamino)ethyl methacrylate (DMAEMA) was attached to the ends of the PU to provide the ionic moiety. Finally, a second network was polymerized from N,N-dimethylacrylamide (DMA) through UV initiation. FTIR analysis was performed to verify the chemical structure. The surface ionic functional groups of the film was determined using dyeing test. Further characterization of the resultant hydrogel included the equilibrium water content (EWC), oxygen permeability (Dk), SEM-EDS, contact angle, tensile tests, protein deposition, and cytotoxicity against L-929 fibroblasts. From the results, this silicone-containing hydrogel can be used for short-term biomedical applications.
Tingling, Dai, and 戴廷玲. "Development and Evaluation of Silicone Hydrogel Contact Lens." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/67904680360409930718.
Full text國立聯合大學
化學工程學系碩士班
103
Oxygen permeability (Dk) and transmissibility (Dk/t) are important parameters used to assess the suitability of contact lenses. The oxygen permeability of the material describes its intrinsic ability to transport oxygen. In this study, we design a novel apparatus to measure Dk and Dk /t of contact lenses by the titration. The apparatus involves accurate measurement of oxygen across the material by allowing the gas (oxygen) to pass through a specially fabricated steel lens model. The expelled gas was collected by dissolution in DI water and the oxygen was measured by titration of the solvent. The Dk and Dk/t values were carried out by this method compared with the oxygen permeability standard values of commercially available contact lenses. The results showed that the method is simple, cost down, requiring no sophisticated equipment as well as giving accurate values in a short time. In addition, there were two types of silicone hydrogel lens materials, HEMA / TEOS and HEMA / TRIS / TEOS, were prepared by the sol-gel process and light polymerization method with suitable components and synthetic conditions. In the HEMA / TEOS recipe, adding 5% of Tetraethyl orthosilicate (TEOS), the Dk and Dk / t values of silicone hydrogel lens are 91 and 75, respectively. The result not only can improve the oxygen permeability effectively, but also is better than that of commercial silicone hydrogel (Dk and Dk / t values were 85 and 45). In the HEMA / TRIS / TEOS recipe, adding 5% of 3-[tris(trimethylsiloxy)silyl]propyl methacrylate(TRIS) into the main recipe 2-Hydroxyethyl methacrylate (HEMA), the Dk and Dk / t values were 114 and 74. These data are similar to the HEMA / TEOS recipe. However, then adding 5% of TEOS into HEMA / TRIS system, which show an excellent oxygen permeability, the Dk and Dk / t values are 136 and 114. This result has been far higher than that of the commercially available products, this recipe for improving the oxygen permeability of the silicone hydrogel contact lenses have a good development potential. Keywords: Oxygen permeability, contact lenses, silicone hydrogel, sol-gel, light polymerization
Lorentz, Holly Irene. "Modeling In Vitro Lipid Deposition on Silicone Hydrogel and Conventional Hydrogel Contact Lens Materials." Thesis, 2011. http://hdl.handle.net/10012/6454.
Full textWANG, YUN-YA, and 王韻雅. "A Patent Analysis of Contact Lens Silicone Hydrogel Technology." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/w9abu8.
Full text逢甲大學
科技管理碩士學位學程
107
In recent years, the proportion of myopia population in Taiwan has continued to rise. Improperly, 3C products and living habits have caused problems in the eyesight of Chinese people, and the age group of myopia has continued to decline. As teenagers and young children are more exposed to 3C products, the ratio of myopia is caused. Continued to rise, in response to advances in technology, myopia is no longer only the choice of glasses as the only corrective choice, more and more people choose contact lenses to wear, most customers for aesthetics, comfort or convenience, so The products have won the hearts of many users, and have become the target of the industry's opponents to imitate learning and transcendence. In the face of such a highly competitive market at home and abroad, in recent years, patents are also the areas in which the four major players in the industry compete. There are always litigations that tell each other that they infringe on their own technology, especially the amount of litigation in the water gel. Therefore, this study will focus on the patented aspects of contact lens hydrophobic glue, using the technology life cycle classification, combined with TRIZ theory, to understand what are the difficulties of this technology at the current stage, what breakthroughs can be made, those can be redeveloped, can give this industry This technology can be used in the future to make recommendations for research and development.
Dan, Hui-Ming, and 鄧卉明. "The Effect of Silicone Monomer on the Membrane Properties and the Surface Wettability of Silicone Hydrogel." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/14596007384691965534.
Full text中原大學
醫學工程研究所
97
Silicone hydrogel contact lenses are new generation contact lenses because of its high oxygen permeability and low protein adsorption, which could increase comfort during wear. These characteristic properties are all attributed to the surface properties of silicone hydrogel. The purpose of this study was to evaluate the effects of 3-(methacryloyloxypropyl)-tris(trimethylsiloxy)silane (TRIS) on the surface properties of silicone hydrogels. In addition, polyvinyl pyrrolidone (PVP) was employed as a surface wetting agent and its effect on the surface hydrophobicity of silicone hydrogel was observed. The silicone hydrogel membrane consisted of 2-hydroxyethyl methacrylate, N,N-dimethylacryl amide, ethylene glycol dimethacrylate and TRIS monomers. In the first part of this study, it was found that the modulus increased from 0.22 MPa to 4.61 MPa as the amount of TRIS increased from 15 to 45 mol%. In addition, the oxygen permeability (DK) of the silicone hydrogel membrane increased from 60 to 110 barrers and the water content decreased from 48% to 13% given the same conditions. Based on these results, a ternary phase diagram was plotted. On the other hand, the second part of this study showed that the wetting agent PVP can notably decrease the contact angle of the membrane from 90o to 78o, bringing its value close to that of conventional contact lenses. In the third part of this study, it was found that significantly low protein adsorption on the membrane was obtained. However, increased membrane adsorption of lipid was found as the TRIS content increased. Lastly, the in vitro cytotoxicity tests showed that the silicone hydrogel and the conventional contact lenses are of the same 1 class according to ASTM F-895 standard. In conclusion, the present study reports various surface properties as a function of the composition of silicone hydrogel. This study suggests that the selection of the TRIS composition depends on a compromise between Dk and the water content of the silicone membranes. Furthermore, a surface wetting agent may be used with silicon hydrogel so as to avoid dry-eye symptom.