ABSTRACT PLASMA SURFACE MODIFICATION AND CHARACTERIZATION OF PMMA FILMS &Ouml / zgen, &Ouml / zge M.Sc., Department of Polymer Science and Technology Supervisor: Prof. Dr. Nesrin Hasirci Co-supervisor: Prof. Dr. Vasif Hasirci December 2011, 114 pages Surface properties play an essential role for determining the behavior of a material for many applications such as coating, printing, adhesion and prosthesis implanting since the surface is the first part that comes in contact with the environment. Although the bulk properties of some materials are at the desired level, the surface may need to be modified for a better compatibility with its surrounding. Plasma treatment is one generally preferred technique because of its high potential to create various functional groups on the surface of the sample by changing the applied plasma parameters. Some molecules can be successfully immobilized onto these surfaces using these specific chemical functional groups created by plasma. The type of the functional group is important for intended purpose of covalent binding of different molecules on the surface of a material. Present study offers important routes for optimization of the surface functionality of (PMMA) films by changing the plasma parameters. For this purpose, solvent casted polymethylmetacrylate PMMA films were modified by, nitrogen, argon and oxygen plasma by using a radiofrequency (RF) generator / and with various powers (10W, 50W, 100W) for different periods (5min, 15min and 30min). The effects of these plasma parameters (gas type, applied power, plasma time) on hydrophilicity, surface free energy, surface chemistry, and surface topography were investigated. Also, the types of surface free radicals created with oxygen plasma treatment were analysed and the decay of these radicals were examined by Electron Spin Resonance Spectroscopy (ESR). In general, plasma treatment reduced the contact angle of PMMA films where the most hydrophilic surface was obtained for 100W 30 min argon plasma treated sample showing superhydrophilic character with the water contact angle value of ~10&deg / . Surface free energy measurements were carried out according to Geometric Mean, Harmonic Mean, Acid-Base approach and it was found that oxygen, nitrogen and argon plasma treatments increased the surface free energy for all samples by increasing the polar components and introducing functional groups on the surface. X-Ray Photoelectron Spectroscopy (XPS) analysis results revealed that free carbonyl and carbonate groups were formed by oxygen plasma treatment, whereas carboxylic acid and free carbonyl groups were formed after argon plasma treatment, and imine, primary amine, amide and nitrozo groups were formed by nitrogen plasma. Atomic Force Microscopy (AFM) analysis revealed that the roughness of the surface increased considerably from ~2 nm to ~75 nm for the 100W 30 min oxygen plasma treated samples. ESR analysis indicated the presence of peroxy radicals on the surface of the oxygen plasma treated PMMA and the intensity of these radicals increased with increasing plasma power. Decay study of the newly created radicals demonstrated that after 1 month under the atmospheric conditions there were still peroxy radicals on the surface of PMMA. This functionality is important in leading time for further process for binding of different molecules to the surface of the materials for specific purposes. As a result, RF plasma was found to be an effective tool for modification of surface properties of materials with product diversity for intended purposes.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O experimento foi realizado no Departamento de Zootecnia da Universidade Federal do Cearà com o objetivo de avaliar o efeito de quatro nÃveis de concentrado (25,0; 37,5; 50,0; 62,5 com base na MS) na raÃÃo de ovinos, sobre o consumo; as digestibilidades aparentes de matÃria seca (MS), matÃria orgÃnica (MO), proteÃna bruta (PB), extrato etÃreo (EE), fibra em detergente neutro (FDN), fibra em detergente neutro corrigida para cinzas e proteÃna (FDNcp), fibra em detergente Ãcido (FDA), carboidratos totais (CT) e carboidratos nÃo-fibrosos (CNF); pH ruminal; as concentraÃÃes amÃnia ruminal (NAR), balanÃo de compostos nitrogenados (BN) e nitrogÃnio ureico plasmÃtico (NUP) Foram utilizados dezesseis ovinos machos, nÃo castrados, da raÃa Santa InÃs, com peso corporal de 26,4kg  4,13kg e aproximadamente sete meses de idade. Os animais foram alojados em gaiolas metabÃlicas individuais, equipadas com coletores e separadores de fezes e urina, bem como cochos para alimento e bebedouros com Ãgua permanentemente à disposiÃÃo. O delineamento experimental utilizado foi em blocos casualizados com quatro tratamentos e quatro repetiÃÃes, totalizando 16 parcelas experimentais. O perÃodo experimental teve duraÃÃo de 28 dias, com 21 dias de adaptaÃÃo e sete dias para coleta de dados. Os animais foram alimentados com raÃÃes contendo feno de Tifton 85 e concentrado (25,0; 37,5; 50,0 e 62,5%). As raÃÃes foram formuladas conforme o NRC (2007) para atenderem aos requisitos nutricionais de ovinos para ganho de 200 g/dia. As raÃÃes foram fornecidas aos animais uma vez ao dia (800h) em forma de mistura total. O consumo de matÃria seca foi determinado pela diferenÃa entre o oferecido e as sobras da raÃÃo ofertada. Amostras dos alimentos, sobras e fezes foram diariamente pesadas e amostradas para subseqente anÃlises quÃmicas. As fezes foram coletadas durante sete dias consecutivos para estimar a digestibilidade dos nutrientes. Os consumos de MS, MO, CT e NDT expressos em g/dia nÃo foram influenciados pelos nÃveis de concentrado da raÃÃo (P>0,05). Comportamento linear crescente foi verificado para os consumos de PB, EE e CNF. Os consumos de FDN, FDNcp e FDA apresentaram comportamento linear decrescente. Para consumo expresso em %PV, registrou-se comportamento linear crescente para MS e decrescente para FDN, comportamento igual foi verificado para o consumo de MS expresso em (g/kg0,75). Os coeficientes de digestibilidade de MS, MO, PB, EE, CT e CNF aumentaram (P<0,05) com o nÃvel de concentrado na raÃÃo. O pH ruminal apresentou comportamento linear para as raÃÃes com menores nÃveis de concentrado e comportamento quadrÃtico para o tratamento experimental com maior nÃvel de concentrado em funÃÃo do tempo pÃs-prandial. As dietas experimentais influenciaram as concentraÃÃes de N-NH3 no rÃmen (NAR) apresentando comportamento linear decrescente para os nÃveis de 37,5 e 50,0% de inclusÃo de concentrado e comportamento quadrÃtico para o nÃvel de inclusÃo 62,5% de concentrado nas raÃÃes. Os nÃveis de concentrado nÃo influenciaram excreÃÃo de NitrogÃnio (N) nas fezes (g/d) e na urina (g/d). O BN foi positivo em todos os nÃveis de concentrado. Os valores de NUP diferiram entre as raÃÃes, apresentando comportamento quadrÃtico. A adiÃÃo de concentrado nas raÃÃes influencia o consumo e a digestibilidade dos nutrientes, os parÃmetros ruminais e promove maior retenÃÃo de compostos nitrogenados no corpo do animal. / The experiment w as conducted at the Department of Animal Scie nce, Federal University of Cear a in order to evaluate the effect of four levels of concentr ate (25.0, 37.5, 50.0, 62.5 on DM basis) in the diet of sheep on intake, digestibility of total dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), neutral detergent fiber corrected for ash and protein (NDF), acid detergent fiber (ADF), total carbohydrates (TC) and non - fiber carbohydrates (NFC ) rumen pH, rumen ammoni a concentrations (NAR), nitrogenous compounds (BN) and plasma urea nitrogen (PUN) . We used sixteen castrated male sheep of Santa Ines body weight of 26.4 kg  4.13 kg and approximately seven months old. The animals were housed in individual metabolic cages equipped with collectors and tabs of feces and urine, and mangers for the supply of food and water fountains with water continuously available. The experimental design was randomized blocks with four treatments and four replications, totaling 16 experimen tal plots. T he experimental period lasted 28 days with 21 days of adaptation and seven days to collect samples. The animals were fed diets containing Tifton 85 hay and concentrate (25.0, 37.5, 50.0 and 62.5% ), which consisted of four experimental treatment s. The diets were formulated according to NRC (2007) to meet the nutritiona l requirements of sheep 200g. day - 1 gain. Diets were fed to animals once a day (800h), in form of a total mixture. Daily consumption of dry matter was determined by the difference be tween the bid and the remains of food offered. Feed samples, orts and feces were daily weighed and sampled for chemical analysis subseqente. Feces were collected for seven consecutive days to estimate the digestibility of dietary nutrients. The DM, OM, TC and NDT in g /d were not affected (P> 0.05) by concentrate feed. Increasing linear behavior was observed for intakes of CP, and NFC. For the intake of NDF, NDF, ADF and these linearly decreased. For consumption expressed as% of BW, there was a linear increasing and decreasing for MS to NDF equal behavior was observed for DM intake expressed in (g / kg 0, 75 ). The digestibility 9 of DM, OM, CP, CT and NSC increased (P <0.05) with the level of dietary concentrate. Rumen pH showed a linear response for diets with lower levels of concentrate and a quadratic for the experimental treatment with high level of concentrate as a function of time post - prandial. The diet influenced the concentrations of NH3 - N in the rumen (NAR) decreased linearly to levels of 37.5 and 50% of the concentrate and a quadratic for the 62.5% level of inclusion of dietary concentrate. The concentrate levels did not influence the excretion of nitrogen (N) in faeces ( g /d ) and urine (g /d ). The NB was positive at all levels of concentrate . PUN values among diets, showing a quadratic behavior. The addition of dietary concentrate influences the consumption and digestibility of nutrients, ruminal and promotes retention of nitrogen in the animal's body.

A huge number of experiments were carried out in the field of nitrogen post-discharges during the last 50 or 60 years and they were supported by many published theoretical works. Some papers were focused also on the nitrogen active discharge, post-discharge itself, or they focused mainly on the kinetic processes running during the post-discharge period. This experimental work shows how oxygen titration into post-discharge will influence nitrogen flowing post-discharge. Experimental data were obtained by optical emission spectrometry, Spectra were measured in the range 300 - 700 nm at laboratory temperature of 300K. Discharge current was kept constant at the value of 120 mA relating to the total discharge power of 145 W. Pressure was kept constant, too, at the value of 1000 Pa. The nitrogen of 99.9999 % purity (further purified by Oxiclear column) flow was adjusted at 0.8 l/min. Flow of oxygen (99.95 % purity) through he titration capillary introduced to post-discharge from down stream direction, was kept at 4 ml/min. Both gas flows were controlled by mass flow controllers. The optical emission spectrometer Jobin Yvon TRIAX 550 with 300 gr/mm grating equipped by liquid nitrogen cooled CCD detector was used for the spectra acquisition. The integration time of 1 s was used at all experiments. The position of titration tube end introduced into post discharge from the down stream side was set from 5 to 25 cm with respect to the end of the active discharge; the step of 1 cm was used. The optical emission spectra were measured at positions from 3 to 29 cm with respect to the active discharge end. The following nitrogen spectral systems were identified in the spectra: 1st positive, 1st negative and 2nd positive. Besides them, some bands of NO-beta system were found. The intensity profiles along the post discharge were obtained for selected vibrational spectral bands of these spectral systems and changes in the vibrational distributions of upper electronic states of these spectral systems were determined.

Clean post-discharge nitrogen plasma and nitrogen plasma with different traces have been focus of scientists for more than 50 years and there were published many articles on theme active discharge, post-discharge, processes and reactions. It is possible to create kinetic models from all these information and then calculate concentrations of elements in atomic form. This diploma thesis is focused on measuring of concentration of atomic nitrogen for different conditions (decay time, pressure, admixture). The titration method by nitric oxide in post-discharge was used to determinate of concentration of atomic nitrogen. All experimental results were obtained by the optical emission spectroscopy. Optical emission spectra were taken in the range of 300-600 nm. DC discharge was created in a quartz tube in a flowing regime. The flowing regime was chosen for this experiment because of better time resolution of decay time, order in milliseconds. Decay time was in the range of 16 – 82 ms for individual experiments. Nitrogen flow was 400 mln/min. Nitrogen oxide flow was in the range of 0-10 mln/min and it was added at the selected post-discharge time. Trace of methane was 0,006 % of the whole volume. Total gas pressure was set on values from 500 to 4000 Pa. The output of discharge was set on constant value of current 150 mA and the output has changed according to the amount of pressure. Nitrogen first positive, second positive and first negative spectral systems, NO spectral system and NO2* spectral system were recognized in all measured spectra. Absolute concentration of atomic nitrogen was specified by the method of titration of NO. Traces of methane increase dissociation of molecular nitrogen and therefore increase the concentration of atomic nitrogen. This thesis brings new results into longtime research of moon Titan and new results into study of processes in nitrogen-methane plasma.