M.Phil / MS
Permanent URI for this collectionhttps://repository.cuilahore.edu.pk/handle/123456789/30
This collection archives the complete set of theses produced by students of the COMSATS University Islamabad, Lahore Campus.
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Item Synthesis of Ag and Cu Nanowires and Deposition of Nanowires Thin Films on to Various Substrates(Library Information Services COMSATS University Islamabad Lahore Campus, 2021-02-26) Saba Qamar; SP19-R06-026; Dr. Muhammad Shahid Nazir; LHR TP 7553Silver and copper nanowires have novel applications because of their unique geometry and physical properties including electrical, optical, thermal and mechanical properties. They are one dimensional metallic structure. These wires have capability to flow ions or electrons in specific directions which is a beneficial characteristic in nanotechnology. Besides efficient performance copper nanowires have limitations including aggregation and oxidation because of their natural characteristics. Silver nanowires also have some limitations for example preservation of morphology in synthesis, feasibility of mass production, environmental stability and thermal stability. In this study, silver and copper nanowires were synthesized through polyol method. FTIR results confirm that Ethylene glycol and Polyvinylpyrrolidone removed in silver and copper nanowires. Liquid conductivity test conforms the conductivity of these materials. The conductivity of silver nanowires reported 716μs/cm and copper nanowires was 387μs/cm. UV visible spectroscopy shows maximum intensity of all silver nanowires are 430nm which matches the adsorption standard of silver, XRD results conform the crystalline structure of both inks and peaks trend matches the standards of silver and copper. and SEM conforms the presence of silver and copper nanowires. Silver nanowires has an average diameter 0.15μm and average length 2.3μm. Copper nanowires has an average diameter 0.07μm and average length 1.1μm, Observed the photocatalytic degradation of silver and copper nanowires using Methylene blue and Congo red dye stock solution respectively. Methylene blue shows 60% degradation and Congo red shows 39% degradation in UV-visible region.Item Investigation of Influence of Thiol Groups on the Drug Loading and Release Properties of Thiolated Derivatives of Cyclodextrin(Library Information Services COMSATS University Islamabad Lahore Campus, 2021-02-26) Hania Sarosh; SP19-R06-028; Dr. Muhammad Ijaz; LHR TP 7554The purpose of this work is to investigate the potential effect of the thiolated and unmodified β-CD on the encapsulation and release efficiency by making its complexes with the drugs. For this investigation, first oxidation of β-CD was done followed by the cysteamine conjugation to β-CD. Ellman’s test was performed to evaluate the no. of thiol groups and disulfide bonds in the thiolated β-CD. Then three drugs namely Fluconazole, Vancomycine and Minoxidil were used to make the inclusion complexes. On one hand their complexes were made with the non-thiolated-β-CD and on the other hand, their complexes were made with thiolated-β-CD. FTIR and XRD analysis were done to check the interactions between the complexes. Drug loading capacity was analyzed by UV Spectrophotometer which illustrated that the thiolated-β-CD complexes have increased drug loading capacity. Drug release time get significant effect in a way that the sustained release of drugs was found for the thiolated-β-CD complexes.Item Effect of Elastomeric Materials on the Thermo-mechanical Behavior of Fiber-reinforced Polymer Composites(Library Information Services COMSATS University Islamabad Lahore Campus, 2021-02-25) Mohammad Ishtiaq; SP19-R06-031; Dr. Zulfiqar Ali; LHR TP 7321Different epoxy-based composites were prepared by using Kevlar fibers (KFs) and glass fibers (GFs) as reinforcement. In the first step, modification of EPDM was done by mixing it with MAH and DCP inside internal mixture followed by mixing of modified EPDM into epoxy by using overhead mixer. In the second step, the mixed solution of epoxy and modified EPDM was poured on fabric layers by hand lay-up method. It was followed compression of composites inside compression molding machine. The composites were characterized in terms of tensile test, Charpy impact test, and bending test to access their mechanical properties. Tensile test results have revealed that KFRP compsoites are ductile whereas GFRP composites are brittle. Moreover, it is indicated by tensile and bending results that addition of EPDM has helped to better mechanical behavior of composite structures. Bending test has shown that flexural properties have been bettered due to increased content of EPDM. According to results of Charpy impact test, the impact strength or energy absorption of composites has bettered with the greater content of EPDM. Therefore, it can be said that KFRP composites are stronger as compared to GFRP composites. It is also inferred that addition of EPDM has helped to prepare mechanically strong compsoites.Item Designing Donor-Acceptor Small Molecules For Organic Solar Cells With Promising Photovoltaic Parameters(Library Information Services COMSATS University Islamabad Lahore Campus, 2021-02-23) Shahzaib Ijaz; SP19-R06-001; Dr. Sobia Tabassum; LHR TP 7340Cyclopentadithiophene (CPT) is one of the most efficient electron donating unit and has been reliably used in highly efficient optoelectronic applications because of its unique characteristics of excitation of electrons by fused thiophene ring derivatives, the rigidity and the high flatness of its structure. In order to meet the increasing demand of high-efficiency photovoltaic compounds in modern high-performance applications, we have designed and explored new CPT-based donor-acceptor-donor-acceptor-donor based materials with higher efficiency from d-CDT(PTTh2). Three novel isostructural D1-A-D2-A-D1 based low band gap small molecule donors (SMDs) having one-atom replacement (Flourine, Chlorine and Hydrogen) in acceptor unit of benzothiadiazole (BTZ) were designed and investigated by density functional theory (DFT) simulations. The designed molecules are 7,7'(7H-cyclopenta[1,2-b:3,4-b']dithiophene-2,5-diyl)bis(6fluoro4(5'hexyl[2,2’[2,2' bithiophen]-5yl)benzo[c][1,2,5]thiadiazole) (CPT1), its chlorine analogue 7,7'-(7H-cyclopenta[1,2-b:3,4-b']dithiophene-2,5-diyl)bis(6-chloro4-(5'-hexyl-[2,2'-bithiophen]-5yl)benzo[c][1,2,5]thiadiazole) (CPT2) and their hydrogen analogue 7,7'-(7H cyclopenta[1,2-b:3,4-b']dithiophene-2,5diyl)bis(4-(5'-hexyl-[2,2'bithiophen]-5 yl)benzo[c][1,2,5]thiadiazole) (CPT3). All are based on the strong electron rich unit CPT and electron withdrawing BTZ acceptors. The structures of designed compounds were optimized at DFT/B3LYP/6- 311 g(d,p). The new designed donors CPT1, CPT2, CPT3 showed superior absorption range found at the wavelengths of 715nm,674nm and 705nm respectively as compared to 667nm of reference molecule d-CDT(PTTh2) in chloroform solution. DFT calculations revealed that CPT1,CPT2 and CPT3 transfer their charges efficiently with band gaps 2.0 eV,2.21 eV and 2.1 eV respectively. The calculated open circuit voltages range from 0.55 eV to 0.70 eV, while CPT2 have a significantly higher open circuit voltage than the open circuit voltage of 0.62 of reference molecule d-CDT(PTTh2). Charge transfer mobilities of designed molecules are also superior than d-CDT(PTTh2) because of their lower reorganization energies ranging from 0.00114 to 0.038282 for electron and 0.11101 to 0.44505 for hole. This DFT investigation revealed that tuning of organic compounds can further enhance the efficiency of SMDs in bulk hetero-junction (BHJ) organic solar cells (OSC’s). DFT calculations showed that one atom substitution has a slight but notable effect on band gaps of frontier molecular orbital (FMOs) which affects the absorption ranges, reorganization energies, Voc, FF and PCE of SMDs in BHJ OSC. Our investigations suggest that the designed molecules can work as fine SMDs when coupled with PC71BM as an acceptor in BHJ OSC.Item Synthesis of Electrochemical Biosensor for Detection of Phosphate in Saliva(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-23) Muhammad Irfan; SP19-R06-029; Dr. Abdur Rahim; LHR TP 7317Calcium phosphate is one of the abundant restoratives and bioactive materials which helps in the restoration of bones and early carious lesions. These re-mineralizing resins are mainly composed in the form of calcium orthophosphate. It is the challenge and need of the day to cure the disease by keeping the amount of calcium phosphate, fluoride, and pH of saliva constant means moderate. Now it is the need of the day to make it possible of performing different medical tests results and cure on the spot in this busy era. For this purpose, an electrochemical biosensor method was introduced. This method is robust, accurate, selective, and sensitive for phosphate detection. The combined effect of metal oxide/graphene oxide nanocomposites has attracted a lot of attention. Iron oxide nanoparticles and their composite have several properties that make them interesting for device applications including catalytic activity, high surface area, electrochemical activity, and oxygen transferability. In this work, doped iron oxide/graphene oxide and iron oxide /reduce graphene oxide nanocomposites have been synthesized by hydrothermal and co-precipitation methods. The synthesized materials Fe2O3/GO and Fe2O3/rGO were characterized by (FTIR, XRD, SEM, EDX, and Raman spectroscopy. The electrochemical analytical techniques (cyclic voltammetry, amperometry, and electrochemical impedance spectroscopy) were used for the evaluation of electrochemical sensing properties. The glassy carbon electrode (GCE) surfaces were modified with the synthesized materials (Fe2O3/GO and Fe2O3/rGO ) and tested as an electrochemical sensor for phosphate detection. The proposed sensors Fe2O3/GO/GCE and Fe2O3/rGO/GCE gave excellent results for the detection of phosphate. The Fe2O3/rGO/GCE sensor gave better results as compared to Fe2O3/rGO/GCE because the rGO is highly conductive as compared to the GO. The sensor did not show any interference from the co-existing species (uric acid, glucose, and H2O2 ). The fabricated sensor successfully detected phosphate.Item Synthesis and Characterization of Metal Oxide Decorated Nanocomposite for Photocatalytic Application(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-23) Rida Fatima Hussain; SP19-R06-017; Dr. Lubna Sherin; LHR TP 6520Dyes present in industrial wastewater are harmful to humans as well as environment. They are non-biodegradable synthetic materials that are difficult to degrade naturally. At present the simplest, economical and ecofriendly method for dye degradation is application of metal oxides nanocomposite as photocatalyst. Fabrication of metal oxide nanocomposites by using safe and cheap natural products for photocatalytic degradation of dyes is highly interesting field in material sciences. This research focuses on synthesis of four different kinds of nanocomposite CoO/Agcl/FeO, CoO/Agcl/NiO, CoO/Agcl/CuO, CoO/Agcl/ZnO which further processed with sodium alginate and form nanocomposite beads. The synthesized nanocomposites beads were characterized by FTIR. Futhure more, synthesized nanocomposite beads were employed as photocatalyst for the degradation of model dye methyl orange . The degradation of model dye was recorded high for Iron/alginate nanocomposite beads(90% in 80 mins) as compared to other nanocomposite beadsItem Synthesis and Characterization of Functionalized Nano-cellulose Based Conducting Material(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-20) Noman Zafar; SP19-R06-006; Dr. Lubna Sherin; LHR TP 6510Electrochemical sensing techniques are the advance techniques for the detection of water contamination. Conducting materials in electro-chemical sensors are based on graphene or carbon nano tubes (CNT) substrate mostly. Resent literature has documented the hazardous effects of graphene and carbon nanotubes (CNT). Moreover, use of these substrates enhances the cost of the sensor to a larger extend. Currently environment friendly and sustainable natural materials are replacing the toxic materials for the development of electro-chemical sensors. In this view current research work aims at the synthesis of conducting composite by incorporating eco-friendly and abundantly available natural material i.e. cellulose as a substrate. Initially nano-cellulose was synthesized and subsequently it was functionalized with polyaniline and nano metal oxides to enhance the conductivity. The synthesized nanocomposite was characterized through FTIR analysis. Conductance of the synthesized materials was checked and IV graphs were plotted. The results showed that conductance of nano composite was increased subsequently by the addition of different metals to NC/PANI composite.Item Design of Novel Lanthanum Doped Al12P12 Nanocages with High Nonlinear Optical Response(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-20) Faiqa Khaliq; SP19-R06-022; Dr. Mazhar Amjad Gilani; LHR TP 6523In current study, the effect of lanthanum doping over Al12N12 and Al12P12 nanocages has been investigated using density functional theory. The strong influence of lanthanum doping on geometrical, electronic, linear, and nonlinear optical properties of Al12N12 and Al12P12 nanocages has been observed. The results revealed that doped nanoclusters possess high thermodynamic stability upto -37.37 kcal/mol and HOMO-LUMO gap is reduced upto 0.89 eV. NBO analysis confirms the charge transfer from metal towards nanocage. The Partial Density of States (PDOS) and Total Density of States (TDOS) strongly support the formation of new HOMO energy level which contributes in the reduction of HOMO-LUMO orbital energy gap. Doping of lanthanum remarkably increases the first hyperpolarizability (βₒ) of the complexes. The highest first hyperpolarizability of 4.43 × 104 au is observed for La@endo-Al12N12 complex. The present investigations intrigue the designing of high performance NLO materials that can be beneficial for their use in modern optoelectronic applications.Item A Non-Enzymatic Dopamine Sensor Based on MoS2 Nanosheets Modified Carbon Cloth (CC) Electrode(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-20) Mariam Sabar; SP19-R06-002; Dr. Sara Riaz; LHR TP 6506Dopaminergic neurons are the source of production of neurotransmitter called as dopamine (DA). It serves as chemical carrier in hormonal, renal, cardiovascular and central nervous system. The behavior of brain related with motivation and reward is controlled by dopamine in humans. The irregular level of dopamine results in many neural diseases which includes Alzheimer’s disease, less attention hyperactivity disease, Parkinson’s disease, schizophrenia as well as restless legs syndrome. It also gives information about probability of drug addiction. For that reason, an accurate method for the detection of dopamine is necessary. Here we described a material consisting of molybdenum disulfide nanosheets (MoS2 NSs) which were deposited on a Carbon Cloth (CC) electrode that is well adapted for sensitive and selective detection of level of dopamine. The molybdenum nanosheets deposited on CC was made by hydrothermal method. The composite was characterized with various characterization techniques like Scanning electron microscope (SEM), Cyclic Voltammetry, Fourier transform infrared spectroscopy (FTIR), Amperometric i-t method and electrochemical impedance spectroscopy. The composite represents excellent electrochemical properties like more electrochemically active surface, large capacitance current, more conductivity and more porosity as shown by different electrochemical studies. The carbon cloth electrode shows good electrocatalytic ability for dopamine oxidation. The electrode operated best at working potential as low as -0.2 V (vs. Ag/AgCl). It responds linearly to dopamine within 0.25mM to 4mM concentration. The sensor has good selectivity, better stability, repeatability and reproducibility.Item Synthesis and Characterization of Imine Linked-Covalent Organic Frameworks for Drug Control Release Studies(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-20) Awais Ali Aslam; SP19-R06-013; Dr. M. Shahid Nazir; LHR TP 6516Covalent organic frameworks (COFs) are new class of emerging porous crystalline materials that have outstanding properties like high surface area, less density and controlled pore size and structure. Owing these outstanding properties COFs proved themselves as excellent materials in numerous fields such as gas separation, gas storage, energy storage, catalysis and biomedical. Based on different building units COFs have been classified into boron containing COFs, imine-based COFs, hydrazine-based COFs and imide-based COFs. Various synthetic approaches have been explored for the construction of COFs such as solvothermal method, microwave method, ionothermal method and room temperature synthesis method. Two factors are very important for the synthesis of COFs, one is selection of building units and second is suitable conditions. Here we synthesize imine linked COF at room temperature. Successful synthesis of imine linked COF-LZU1 was done by the condensation reaction between Triformyl benzene and 1,4-diaminobenzene. COF-LZU1 was modified with Ag particles by the reaction between silver nitrate and COF-LZU1. Synthesis of COF-LZU1 and Ag@COF-LZU1 was confirmed by FTIR and XRD. In FTIR spectra C=N appears at 1616 cm-1 that confirms the condensation reaction between two selected monomers. In XRD strong diffraction peak at 2Ɵ at 4.78o confirms the crystalline nature of COF-LZU1. COF-LZU1 showed the photocatalytic degradation of MB and CR dyes in visible light with percentage degradation of 72.21 and 67.7, respectively.
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