NANOPOLYMERS

PRESENTED BY:KARISHMA GUPTACH 8225

INTRODUCTION

An example of a nanopolymer is silicon nanospheres of size 40 – 100 nm and they are much harder than silicon, their hardness being between that of sapphire and diamond.

Nanopolymer is a polymer or copolymer having dispersed in its nanoparticles. These may be of different shapes (e.g. platelets, fibers, spheroids), but at least one dimension must be in the range of 1 to 100 nm. The transition from micro- to nano-particles lead to change in its physical as well as chemical properties. The major factor in this is the increase in the ratio of the surface area to volume which leads to an increasing dominance of the behavior of atoms on the surface area of particle over that of those interior of the particle. This affects the properties of the particles when they are reacting with other particles.

PROPERTIES OF NANOPOLYMER COMPOSITES

1. FLEXIBILITY2. CONDUCTIVITY: Nanotubes can conduct heat and

electricity far better than copper, and are already being used in polymers to control or enhance conductivity.

3. STRENGTH and LIGHT WEIGHT : Carbon nanotubes are at least 100 times stronger than steel, but only one-sixth as heavy – so nanotube fibers could strengthen just about any material.

4. DURABILITY

CLASSIFICATION OF NANOPOLYMERSConductive Polymers

Many nanoparticles are metals and are good conductors of electricity.There are called conductive polymers or organic metals. Polyacetylene is an example. The high electrical conductivity of conductive polymers such as polyacetylene and polyaniline can be explained on the basis of their nanostructure involving primary particles with a metallic core of diameter 8 nm surrounded by an amorphous nonconducting layer 0.08nm thick of the same [C2H2]n, composition.

Sketch of the nanostructure of a polyacetylene conductive polymer showing the9.6-nm-diameter nanoparticles. The top halves of several of these nanoparticles have been removed to display the 8-nm-diameter metallic core and the 0.8-nm-thick surrounding amorphous coating.

Block Copolymers A copolymer is a macromolecule containing two or more types of monomers. In many cases one polymer component is water-soluble and the other is not. Some examples of nanostructures fabricated from copolymers are hairy nanospheres, star polymers, and polymer brushes.

Star polymers are used in industry to improve the melt strength, that is, the mechanical properties of molten plastic materials.

Hairy nanospheres have been employed for the removal of organic compounds from water, both in a dispersed form and as solid microparticles.

Polymer brushes are effective for dispersing latex and pigment particles in paint.

PREPARATION OF NANOPOLYMERS

Nanopolymers are prepared in many ways. The preparation of nanofibers, core shell fibers, hollow fibers, and tubes from synthetic polymers with diameters down to a few a nanometers can be done in many ways like:

1. VAPOR CONDENSATION 2. VACUUM EVAPORATION ON RUNNING LIQUIDS

METHOD (VERL) 3. ELECTRO-SPINNING

VAPOR CONDENSATION PROCESS

This process is used to make the metal oxide ceramic nanopolymers. It involves evaporation of solid metal followed by rapid condensation to form nano-sized clusters. Various approaches to vaporize the metal can be used and variation of the medium in which the vapor is released affects the size of the particles. Inert gases are used to avoid oxygen while creating nanopolymers.

VACUUM EVAPORATION ON RUNNING LIQUIDS METHOD (VERL)

This method (VERL) is a variation of vapor condensation method and uses a thin film of a relatively viscous material, oil, or a polymer, on a rotating drum. Vacuum is maintained in the apparatus and the desired metal is evaporated or spurted in vacuum. Particles form in the suspensions in the liquid and can be grown in the process.

ELECTRO-SPINNING METHOD

This method is the most useful method in the manufacture of the polymers in the nano scale compared to the above two methods that are described. Electro-Spinning is a process that utilizes electrical force to produce polymer fibers from polymer solutions or melts. The obvious advantage of the electro-spinning technique is that, it produces ultra-fine fibers, with huge surface-to –volume ratio, which have great application potentials in many fields such as protective clothing, air filtration, sensors, drug delivery system, sensors, protective textile, and as fiber templates for preparation of nanotubes

The principle on which this technique based is basically very simple as when polymer solution is kept in capillary tube a force of surface tension is developed at the tip of capillary which causes the solution to remain in capillary. If certain electrical voltage is supplied to the tip of the solution, it is ejected from capillary because of the repulsive forces generated in the form of a jet which is collected on a screen which is charge that of capillary tip.The nanofiber web is obtained on the screen, which can be then transformed in nonwoven web, or instead of screen if tip of roller is placed, then a continuous strand can be obtained as filament nanofiber. This method is highly précised and gives high strength to fiber i.e. Almost 17 times stronger than Kevlar

PRINCIPLE

BIO-HYBRID NANOFIBRES BY ELECTROSPINNING

Polymer fibers are produced on a technical scale by extrusion, i.e., a polymer melt or a polymer solution is pumped through cylindrical dies and spun/drawn by a take-up device. The resulting fibers have diameters typically on the 10-µm scale or above. To come down in diameter into the range of nanometers, electrospinning is today still the leading polymer processing technique available. A strong electric field of the order of 103 V/cm is applied to the polymer solution droplets emerging from a cylindrical die. The electric charges, which are accumulated on the surface of the droplet, cause droplet deformation along the field direction, even though the surface tension counteracts droplet evolution. In supercritical electric fields, the field strength overbears the surface tension and a fluid jet emanates from the droplet tip. The jet is accelerated towards the counter electrode. During this transport phase, the jet is subjected to strong electrically driven circular bending motions that cause a strong elongation and thinning of the jet, a solvent evaporation until, finally, the solid nanofibre is deposited on the counter electrode which are, in principle, infinitively long. For a broad range of applications including catalysis, tissue engineering, and surface modification of implants this infinite length is an advantage.

BIO-HYBRID POLYMER NANOTUBES BY WETTING

In some applications like inhalation therapy or systemic drug delivery, a well-defined length is required. This requires the preparation of nanotubes and nanorods with very high precision. The basic concept of this method is to exploit wetting processes. A polymer melt or solution is brought in contact with the pores located in materials characterized by high energy surfaces such as aluminum or silicon. Wetting sets in and covers the walls of the pores with a thin film with a thickness of the order of a few tens of nm. It is known from experiments that low molar mass systems tend to fill the pores completely, whereas polymers of sufficient chain length just cover the walls. To obtain nanotubes, the polymer/template system is cooled down to room temperature or the solvent is evaporated, yielding pores covered with solid layers. The resulting tubes can be removed by mechanical forces for tubes up to 10 µm in length, i.e., by just drawing them out from the pores or by selectively dissolving the template. The diameter of the nanotubes, the distribution of the diameter, the homogeneity along the tubes, and the lengths can be controlled.

APPLICATIONS

Bioinspired nano polymer micelles imaged by electron microscopy (left) and atomic force microscopy (right)

Polymer nano micelles are an attractive option for nanoscale targeted drug delivery for treatment of diseases such as cancer.

HD POXY is a modern nano polymer sealant car wax designed to seal and protect all hard exterior surfaces, including paint, glass, plastic, wheels and polished metal

Armor: Hull is made of titanium-alloy over nanopolymer interior plates.

ultra-high capacity nano-polymer battery

New Biodegradable Biocompatible Citric Acid Nano Polymers for Cell Culture Growth & Implantation

FIG. shows SEM pictures of A) a cross section of a POC

biphasic scaffold; B) the pore structure of the porous

phase; C) human aortic smooth muscles

cells on the porous phase of co-cultured biphasic scaffold;

D) human aortic endothelial cells on the lumen of co-cultured biphasic scaffold.

THANKYOU