Objects of Nanochemistry and Unique Properties of Nanoparticles

Purpose of lecture –presentation:
Study of objects of Nanochemistry and their properties

Plan of lecture –presentation:
1. Objects of Nanochemistry
2. Classification of Nanochemistry Objects
3. Properties of Some Nanoparticles

1. Objects of Nanochemistry
Basic Objects if Nanochemical Investigations

1. Objects of Nanochemistry
Fullerenes or Buckyballs - pure carbon, cage-like molecules composed of at least 20 atoms of carbon. The word ‘fullerene’ is derived from the word “Buckminsterfullerene,” which refers specifically to the C60 molecule and is named after Richard Buckminster Fuller, an architect who described and made famous the geodesic dome. C60 and C70 are the most common and easy to produce fullerenes.

1. Objects of Nanochemistry
Fullerene C60 molecule

1. Objects of Nanochemistry
For С70 molecule it was suggested the structure with ellipsoidal form of symmetry D5h. Polyedric clusters of carbon were named fullerenes and the most used molecule С60 — buckminsterfullerene, after American architect Buckminster Fuller.

1. Objects of Nanochemistry
In fullerenes molecules carbon atoms are situated in the tops of regular six and fife cornered structures which compose the surface of sphere or ellipsoid. The most symmetric and studied representative of fullerenes – fullerene C60, in which carbon atoms form multifaced structure consisting of 20 six cornered and 12 five cornered structures and looks like football ball.

1. Objects of Nanochemistry
The next widely used is fullerene C70, which differs from fullerene C60 by insert of belt of 10 carbon atoms in equatorial area of C60, as the result, C70 molecule looks like the ball for rugby.

1. Objects of Nanochemistry
Fullerenes С20 – С70 family

1. Objects of Nanochemistry
Carbon Nanotubes - carbon based tubular structures with dimensions in nanometer regime which consist from one or several hexagonal graphite tubes (graphenes) and end with semispherical head.

1. Objects of Nanochemistry
Ideal model of one layered carbon nanotube

1. Objects of Nanochemistry
Nanotubes are mostly classified according to the type of rolling of graphite plane which is characterized by two numbers n and m that determine the division of rolling direction to the vectors of graphite grid translation.
According to the values of parameters (n, m) there are:
1) «armchair» n=m
2) zigzag m=0 or n=0
3) spiral (hiral) nanotubes m ≠ n

1. Objects of Nanochemistry
Models of cross cut of multilayered nanotubes: a – russian dolls (“matreshka”); б - roll

1. Objects of Nanochemistry
Inorganic Nanocrystals
Whiskers – (hair, mustache, inorganic fibers) – thread typed crystals with diameter from 1 to 10 mkm and length / width ratio >1000
Whiskers: thread typed crystals of SnO2,

1. Objects of Nanochemistry
Manganites – compounds with the effect of colossal magnetic resistance (CMR).
Beginning with the 20-th of the XX century it was known that electrons that form electric current in electric chain have their own magnetic moment, spin. But this was not used in practice. With the beginning of new century new field of science – magneto electronics (spintronics) – appeared.

1. Objects of Nanochemistry
Effect of CMR was found out in manganites family with general formula Ln1-xAxMnO3 (Ln – rare earth element, A – alkali or alkali earth element) and structure of perovskite. The basic mechanism of charge transfer for this class of materials is mechanism of double change Mn3+ - O - Mn4+. There were also found other families of materials with CMR effect: La1-xAxCoO3, halcogenides based on chromium, pyro chlorine family Tl2Mn2O7 etc.

1. Objects of Nanochemistry
Photonic crystal – material with structure characterized by periodic change of refraction index in spatial dimensions.
Photonic crystals: а – opal – natural photonic crystal; б, в – micro photographs of one mode (125 microns in diameter) optic fiber’s cross-sections

1. Objects of Nanochemistry
Bio ceramics – structural material compatible with biological objects, which is used in practical medicine for making prosthesis and implants

1. Objects of Nanochemistry
Diamondoids - nanometer-sized structures derived from the diamond crystal structure.
As nanotechnologies developed the idea of existence of diamondoids - smallest bricks from which crystal of macroscopic diamond consists. Such elemental bricks-molecules were named adamantane (C10H16), diadamantane (C14H20) and triadamantane (C18H24)

1. Objects of Nanochemistry
In 1957 diamondoids were found in crude oil. Due to characteristics similar to those of diamond diamondoids are widely used in different fields of life: microelectronics, nanoelectronics, medicine (pic. 2.9), machine building, metals treatment, engines building, aviation and automobiles building.
Medical nanorobot made from diamondoids

1. Objects of Nanochemistry
Clusters
NaCl cluster – ionic cluster
Fractal cluster
Molecular cluster of ferredoxine

1. Objects of Nanochemistry
Clusters in gases. In the present rate of global Earth temperature gross and rate of greenhouse gases concentration increase exceed more than for one order characteristics of all earlier warming periods. Clusterization of water vapor in atmosphere is the factor that influences the heat balance of Earth atmosphere.
Configurations of clusters: а – (Н2О)20 и б – (Н2О)90, corresponding to 20ps. Coordinates are shown in nm.

1. Objects of Nanochemistry
Configurations of clusters: а – (СО2)10(Н2О)10, б – (N2O)10(Н2О)10, corresponding to 20ps. Coordinates are shown in nm.

2. Classification of Nanochemistry Objects
Objects of Nanochemistry

The United Classification of Nanochemistry Objects

2. Classification of Nanochemistry Objects
Quantum dot (QD) – three-dimensional potential pit for quantum particle, limiting movements of the last in three directions, it has sizes about the length of de-Broil wave of quantum particle.
Physically QD can be realized on form of double heterostructure in which narrow zoned semiconductor is placed in the matrix of wide zoned semiconductor as small inclusion. In this case three-dimensional quantum pit (or quantum dot) forms for the charge carriers in the area of narrow zoned semiconductor.

2. Classification of Nanochemistry Objects
Physically QD can be realized on form of double heterostructure in which narrow zoned semiconductor is placed in the matrix of wide zoned semiconductor as small inclusion. In this case three-dimensional quantum pit (or quantum dot) forms for the charge carriers in the area of narrow zoned semiconductor.
Quantum dot
Quantum threads (manganite whiskers)

2. Classification of Nanochemistry Objects
Quantum thread (wire) — two-dimensional potential pit for quantum particle which sizes in two dimensional directions ~ the length of de-Broil wave of quantum particle. Particularity of quantum particle’s movement in the direction normal to the quantum wire’s axis is that the set of allowed values of energy of movements in mentioned directions is discreet.

2. Classification of Nanochemistry Objects
Quantum (pit) hole – one dimensional potential hole for quantum particle with sizes proportional to de-Broil wave length of quantum particle. Characteristic feature of quantum particle’s movement is that the set of allowed energies is discreet.

2. Classification of Nanochemistry Objects
Graphen (nanothin)

3. Properties of Some Nanoparticles
The unique properties of these various types of intentionally produced nanomaterials give them novel electrical, catalytic, magnetic, mechanical, thermal, or imaging features that are highly desirable for applications in commercial, medical, military, and environmental sectors. These materials may also find their way into more complex nanostructures and systems.

3. Properties of Some Nanoparticles
Zinc oxide:
Ability to adsorb wide spectrum of electromagnetic rays (UV, IR, microwaves, radio waves).

3. Properties of Some Nanoparticles
Silica dioxide:
- Coating from silica dioxide nanoparticles defends the surface from dust and moisture.

3. Properties of Some Nanoparticles
Silver nanoparticles’ properties:
Phenomenal bactericide and antivirus activity (silver nanoparticles are thousand times effective then silver ions);
Silver nanoparticles act very selectively – they affect only for viruses, cells are not destroyed;
High electric conductivity.

Check Yourself
List the basic objects of nanochemical investigations.
Give the definition of fullerenes (buckyballs) and name the most widely used ones.
Give the definition of carbon nanotubes and name their properties.
How are nanotubes classified?
What is called whiskers?
What are the properties of manganites?
What are the properties of photonic crystals?
List the applications of bioceramics.
Give the definition of diamondoids and name their properties.
Give the definition of clusters and name their properties.
What is quantum dot? What are its properties?
What is quantum wire? What are its properties?
What is quantum pit? What are its properties?