sol gel synthesis (1).pptx

sol gel synthesis

1. Government Vidharbha Institute Of Science and Humanities, Amravati Department Of Physics and Electronics Seminar on SOL-GEL SYNTHESIS METHOD PRESENTED BY SAMIKSHA R. DEOLE (M.Sc. II)

2. Nanotechnology Classification of Synthesis Methods Sol Gel Method Advantages Disadvantages CONTENT

3. Nanomaterials are commonly defined as materials with an average grain size less than 100 nm . Nanotecnology it is the study of manipulating matter on a atomic and molecular scale generally nanotecnology deals with developing materials having at least one dimension sized ranges from 1to 100 nm . What is Nanotechnology

4. Basically synthesis methods are divided into

5. It is a bottom up approach of synthesis which is in use in 1800s Sol gel method is a wet chemical based self assembly process for nanomaterial formation. The sol gel process as the name implies involves evaluation of network through the formation of a colloidal suspension. The precursors used in this process for synthesizing colloidal generally consist of metal alkoxide. Sol Gel Method

6. Hydrolysis Condensation Growth of particles Agglomeration of particles Sol-Gel process occurs in four stages:

7. In hydrolysis, addition of water replaces alkoxy groups(OR) with hydroxy group (OH) Hydrolysis occurs by attack of oxygen on silicon atom in silica gel. A catalyst such as HCl and NH 3 accelerates the hydrolysis Hydrolysis continue until all (OR)groups are replaced by (OH) groups Hydrolysis

8. Polymerization to form siloxane bond occurs by either a water producing or alcohol producing condensation reaction Condensation reaction finally results in the formation of monomer, dimer, cyclic, tetramer, and high order rings Condensation

9. All the steps in this process are dependent on several initial conditions such as pH value of the sol, temperature of the reaction, concentration of reagent, time of reaction, nature and concentration of catalyst. By controlling this parameters it is possible to vary the structural, electrical and optical properties of sol gel Once the gel is formed there are several ways to convert this gel to the desired solid form .

10. Sol gel method of thin film deposition is a cheap and low temperature technique. Sol-gel process can produce thick coating to provide corrosion protection performance. Sol gel is a versatile process as it can produce aerogels, xerogels , ceramic materials nano powders, nanostructured thin films. Advantages

11. The Cost of the raw materials may be high as compared to mineral based metal ion sources Being a multi-step process, close monitoring is required The Process is not very clean. It contents undesired atoms, molecules, ions etc. which deteriorates electrical and optical properties of deposited materials Disadvantages

12. Thank You !