This document discusses various methods for synthesizing nanomaterials, including top-down and bottom-up approaches. The top-down approach involves breaking down bulk materials into nanoparticles, using methods like attrition and lithography. The bottom-up approach involves building nanoparticles from molecular precursors using methods like pyrolysis, solvothermal processes, and sol-gel techniques. These synthetic methods allow for the production of nanomaterials with applications in areas like drug delivery, coatings, and imaging. Further development could improve biological imaging and cancer treatment.

1. Synthesis Of Nano
Materials

2. Introduction
 Nanomaterials describe, in principle, materials of which
a single unit is sized (in at least one dimension) between
1 and 1000 nanometres.
 Biological systems often feature natural, functional
nanomaterials. The structure of foraminifera and viruses
(capsid), the wax crystals covering a lotus or nasturtium
leaf, spider and spider-mite silk are few examples of
natural nanomaterials.

3.  Natural inorganic nanomaterials occur through crystal
growth in the diverse chemical conditions of the earth's
crust. For example clays display complex
nanostructures due to anisotropy of their underlying
crystal structure, and volcanic activity can give rise to
opals, which are an instance of a naturally occurring
photonic crystals due to their nanoscale structure.
Introduction

4. Photonic Crystals
 A photonic crystal is a periodic optical nanostructure
that affects the motion of photons. They are used to
manipulate light flow. Used to form colour changing
paints and inks.

5. Synthesis
 Includes two methods
 Bottom Up Approach
 Top Down Approach

6. Top Down
 Start with bulk material and “cut away material “ to
make what you want.
 Examples:
ATTRITION: In attrition, macro- or micro-scale
particles are ground in a ball mill, a planetary ball
mill, or other size-reducing mechanism. The resulting
particles are air classified to recover nanoparticles.

7. Top Down
 Lithography : It is a wafer scale process to prepare
homogenous 1D,2D or 3D nanomaterials.
 The method combines the advantages of both top
down and bottom up approaches and is a two step
process :
 The preparation of colloidal crystal mask (CCM) made of nano
spheres.
 The decomposition of desired material through the mask.
 The mask is then removed and the layer keeps the ordered pattern
of the mask interstices.

8. Bottom Up
 Building what you want by assembling it from
building blocks (Such as atoms and molecules).
 Chaotic
 Chaotic processes involve elevating the constituent
atoms or molecules to a chaotic state and then
suddenly changing the conditions so as to make
that state unstable. Through the clever manipulation
of any number of parameters, products form largely
as a result of the insuring kinetics.

9. Bottom Up
 Controlled
Controlled Processes involve the controlled
delivery of the constituent atoms or
molecules to the site(s) of nanoparticle
formation such that the nanoparticle can
grow to a prescribed sizes in a controlled
manner.

10. Bottom Up
 Bottom up approach are further classified into
1.) Gas (Vapor) Phase Fabrication: Pyrolysis
2.) Liquid Phase Fabrication: Solvothermal Reaction, Sol-
gel.

11. Bottom Up Approach Types

12. Pyrolysis
 In pyrolysis, a vaporous precursor (liquid or gas) is
forced through a hole or opening at high pressure and
burned. The resulting solid is air classified to recover
oxide particles from by-product gases. Pyrolysis often
results in aggregates and agglomerates rather than
singleton primary particles.
 The advantages of vapor phase pyrolysis include it
being a simple process, cost effective, a continuous
operation with high yield.

13. Solvothermal Process
 Precursors are dissolved in hot solvents (e.g., n-butyl
alcohol) and solvent other than water can provide
milder and friendlier reaction conditions. If the solvent is
water then the process is referred to as hydrothermal
method.
 It is synthesis method for growing for crystals from a non
aqueous solution in a autoenclave (a thick walled steel
vessel) at high temperature ( 400 deg.C) and pressure.

14. Sol-Gel
 The sol-gel process is a wet-chemical technique (also
known as chemical solution deposition) widely used
recently in the fields of materials science and ceramic
engineering.

15. Steps Include
 Formation of stable sol.
 Gelation via a polycondensation or polyesterification
reaction.
 Gel aging into a solid mass. This causes contraction of
the gel network, also phase transformations and
Ostwald ripening.
 Drying of the gel to remove liquid phases. This can lead
to fundamental changes in the structure of the gel.

16. Steps Include
 Dehydration at temperatures as high as 8000 degree C,
used to remove M-OH groups for stabilizing the gel, i.e.,
to protect it from rehydration.
 Densification and decomposition of the gels at high
temperatures (T > 8000 degree C), i.e., to collapse the
pores in the gel network and to drive out remaining
organic contaminants

17. Applications
 Drug delivery systems
 Anti-corrosion barrier coatings
 UV protection gels
 Lubricants and scratch free paints
 New fire retardant materials
 New scratch/abrasion resistant materials
 Superior strength fibres and films

18. Future Works
 Nanoparticles can provide significant improvements in
traditional biological imaging of cells and tissues using
fluorescence microscopy as well as in modern
magnetic resonance imaging (MRI) of various regions
of the body.
 Among the different application areas of
nanoparticles, drug delivery is one of the most
advanced. This is large part due to the success of
polymer- and liposome-based drug delivery systems.

19. Future Works
 Nanoparticles have made a tremendous impact in the
treatment of various types of cancer, as evidenced by
the numerous nanoparticle-based drugs and delivery
systems. Paclitaxel is an anti-cancer agent used to treat
several types of cancer (such as ovarian, skin,
esophageal, and lung).

20. References
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