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Title of Thesis

Muhammad Raffi
Institute/University/Department Details
Department of Chemical and Materials Engineering / Institute of Engineering and Applied Sciences Islamabad
Chemical and Materials Engineering
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
metal nanoparticles, inert gas condensation, escherichia coli, optical density, colony forming units, nanocomposites, titania nanoparticles, silver-polymer nanocomposites, silver nanoparticles, silver-silica nanocomposite, sol gel, silver-silica nanocomposites,

This dissertation is about the science on atomic scale- an interdisciplinary approach to nanoparticles. Studies on the preparation of nanoparticles using both physical and chemical methods are presented. Understanding and controlling the process parameters for nanoparticles growth during synthesis are the keys towards successful fabrication of materials with tailored properties. The relationship between the process parameters, structure and physical properties of nanoparticles has been examined.

Sol gel, a chemical method was used for synthesis of silver nanoparticles in silica matrix. Thin coatings of sol were applied on the microscope glass slides. These sol coated samples were oxidized and subsequently reduced in pure hydrogen environment. Effect of annealing environment and temperature on the formation of silver nanoparticles in the matrix were studied. Structural and optical characterizations of the samples were carried out by X- ray diffraction, Scanning electron microscopy and DV-Vis spectroscopy. Growth of silver nanoparticles size in silica has also been analyzed by a theoretical model based on the diffusion and coalescence processes.

Silver nanoparticles were also synthesized by inert gas condensation (IGC) method using argon and flowing helium gas in the process chamber. Effect of process parameters, such as metal evaporation temperature and helium pressure, on the particle crystallinity, morphology, size and distribution was examined. These silver nanoparticles were found impurity free, having a narrow distribution. Structural characterization of nanoparticles was carried out by X- ray diffraction and transmission electron microscopy. Based on the experimental results and theoretical model of surface free energy and undercooling as a function of evaporation temperature and inert gas pressure, nanoparticles formation was analyzed.

Antibacterial characterization of silver nanoparticles synthesized by IGC was carried out both in liquid and solid growth media against Escherichia coli (E. coli). A known number of bacterial cells were incubated with a range of silver nanoparticles concentration. The bacterial growth was characterized by periodic measurement of optical density (OD) of solution and estimation of colony forming units (CFU) on solid growth medium. Interaction of silver nanoparticles with bacterial cells was observed with scanning and transmission electron microscopy. Silver-doped-titania nanoparticles were synthesized by sol-gel method, containing a range of doped atom percent silver. Structural characterization of these nanoparticles was carried out by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Antibacterial studies of silver-doped-titania were carried out against E. coli both in liquid and solid growth media. A known number of bacterial cells were incubated with silver-doped-titania nanoparticles to study the growth patterns by periodically measuring OD and estimation of CFU. Bactericidal behavior of silver-doped-titania nanoparticles was compared with the antibacterial effect of pure Ti02 and pure silver nanoparticles.

Download Full Thesis
1276.61 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
141.69 KB
2 1 Introduction 1
68.55 KB
  1.1 Introduction To Nanomaterials 1
  1.2 Outline Of The Dissertation 3
  1.3 References 5
3 2 Review Of Nanomaterials 6
268.8 KB
  2.1 Synthesis Of Nanomaterials 6
  2.2 Nanocomposites Synthesized By Sol-Gel 7
  2.3 Synthesis Of Titania Nanoparticles For Environmental Studies 11
  2.4 Synthesis Of Nanoparticles By Inert Gas Condensation (IGC ) 14
  2.5 Silver-Polymer Nanocomposites 18
  2.6 Antibacterial Studies Of Silver Nanoparticles And Nanocomposites 21
  2.7 References 25
4 3 Nanoparticles Synthesis And Characterization Techniques 30
205.48 KB
  3.1 Synthesis Of Silver-Silica Nanocomposite By Sol Gel 30
  3.2 Synthesis Of Nanoparticles By Inert Gas Condensation ( Igc ) Method 31
  3.3 Nanoparticles Characterization Techniques 36
  3.4 References 44
5 4 Synthesis Of Silver-Silica Nanocomposites By Sol-Gel 45
135.06 KB
  4.1 Introduction 45
  4.2 Experimental Setup 45
  4.3 Results 46
  4.4 Discussion 51
  4.5 References 54
6 5 Studies On The Growth Parameters Of Inert Gas Condensation Method To Synthesize Silver Nanoparticles 56
221.03 KB
  5.1 Introduction 56
  5.2 Experimental Setup 57
  5.3 Results 57
  5.4 Discussion 64
  5.5 References 69
7 6 Antibacterial Efficacy Studies Of Silver Nanoparticles Against Escherichia Coli Attcc-15224 70
158.29 KB
  6.1 Introduction 70
  6.2 Experimental Setup 71
  6.3 Results 72
  6.4 Discussion 76
  6.5 References 80
8 7 Antibacterial Properties Of Silver-Doped- Titania 81
164.07 KB
  7.1 Introduction 82
  7.2 Experimental Setup 82
  7.3 Results 83
  7.4 Discussion 88
  7.5 References 92
9 8 Conclusions And Suggestions For Future Work 93
58.26 KB