Unit 3 – The Chemistry of Engineering Materials Engineered Nanomaterials

Question 1

italicize

__________has attractive properties and amazing technological possibilities, which can be any one of the four basic types - metals, ceramics, polymers or composites.

Answer 1

nanomaterials

Question 2

four basic types of nanomaterials

Answer 2

metals
ceramics
polymers
composites

Question 3

fill in the blanks

The first – and broadest – definition of nanomaterials states that, these are materials where the sizes of the individual building blocks are less than _________ (a very small scale), at
least in one dimension (nm; equivalent to the diameter of approximately 500 atoms).

Answer 3

100 nm

Question 4

The main difference between nanotechnology and conventional technologies is that the “bottom-up” approach is favored in _____________, whereas ____________
generally use the “top-down” approach.

Answer 4

nanotechnology
conventional technologies

Question 5

nanotechnology uses what approach

Answer 5

bottom-up approach

Question 6

conventional technologies use what approach

Answer 6

top-down approach

Question 7

the expression _________ means starting from large pieces of material and producing the expected structure by mechanical or chemical methods.

Answer 7

top-down

Question 8

__________ are produced via top-down processes, starting from bulk materials. The intended product is obtained by the application of mechanical and/or
chemical processes

Answer 8

Conventional goods

Question 9

in “_________” processes where atoms or molecules are
used as the building blocks to produce nanoparticles, nanotubes, or nanorods, or thin films
or layered structures.

Answer 9

bottom-up

Question 10

The
_______
starting with atoms and molecules as the building blocks that produced particles, nanotubes or nanorods and these products are also characterized
by their dimensionality.

Answer 10

bottom-up process

Question 11

one-dimensional nanoparticles

Answer 11

nanotubes and nanorods

Question 12

zero-dimensional structure

Answer 12

nanoparticles and fullerenes

Question 13

two-dimensional

Answer 13

nanoplates (graphenes)

Question 14

The _____________ of the diffraction pattern indicates that the direction of the platelets was perpendicular to the faces of the platelet;

Answer 14

hexagonal symmetry

Question 15

In the formation of nanorods and nanoplates, the influence of
___________ is to be considered.

Answer 15

surface energy

Question 16

At the circumference of each layer, the bonds are not saturated. The ___________ (short lines) need additional energy; thus, there is a strong tendency to saturate these bonds.

Answer 16

dangling bonds

Question 17

Italicize

is the most important compound in this context with an ideal composition of Al2SiO3(OH)4.

Answer 17

Imogolite

Question 18

_____________ tubes with the ideal composition are very narrow, with internal diameters of 1 nm and external diameters of 2 nm.

Answer 18

Imogolite

Question 19

Discussions about graphite and fullerenes as special modification of carbon is essential in order to understand _________________________.

Answer 19

carbon nanotubes

Question 20

Structure of graphite:
Each layer consists of interconnected ____________ with one carbon atom at each vertex.

Answer 20

hexagon

Question 21

Italicize

These single layers of graphite are known as __________, and because of its structure and bonding it is often denominated as an infinitely extended, two-dimensional aromatic compound.

Answer 21

graphene

Question 22

In ___________), one observes single bonds only, as nitrogen as well as boron are both in their three valency state.

Answer 22

boron nitride (BN

Question 23

In the sense that graphene is a two-dimensional aromatic compound, __________, which also exist in the case of BN, are three-dimensional aromatics.

Answer 23

fullerenes

Question 24

they are consist of a
combination of hexagons and pentagons;

Answer 24

fullerenes

Question 25

The most common fullerene, and the first to be identified consists of ____ carbon atoms, with the molecular structure comprising 12 pentagons and 20 hexagons.

Answer 25

C60

Question 26

The fullerene with the least number of carbon which is identified (experimentally) is ___ while the smallest stable fullerene is ____.

Answer 26

C20 C36

Question 27

Fullerenes also appear quite often in many layers; these aggregates are known as “___________” or “____________.”

Answer 27

nested fullerenes onion molecules

Question 28

__________ are formed by wrapping graphene layers of limited size to form a tube.

Answer 28

Nanotubes

Question 29

The formation of nanotubes is not limited to single graphene layers and, as for fullerenes, both “_____” and “_________” nanotubes may be observed.

Answer 29

multiwall single-wall

Question 30

The ______________ consist of a series of coiled graphene layers and can be described perfectly using electron microscopy

Answer 30

multiwall nanotubes

Question 31

Nanocarbons which are a class of recently discovered materials have innovative and exceptional properties and are currently being used in some ___________ technologies and will certainly play an important role in future high-tech applications.

Answer 31

cutting-edge

Question 32

Three nanocarbons that play role in future high-tech applications are ________________.

Answer 32

fullerenes, carbon nanotubes, and graphene

Question 33

# Italicized The material composed of C60 molecules is known as ____________

Answer 33

buckminsterfullerene

Question 34

short term for buckminsterfullerene

Answer 34

buckyball

Question 35

# Italicized In the solid state, the C60 units form a crystalline structure and pack together in a face- centered cubic array. This material is called ________,

Answer 35

fullerite

Question 36

Some of these compounds involve atoms or groups of atoms that are enclosed within the cage of carbon atoms (and are termed _________________).

Answer 36

endohedral fullerenes

Question 37

For other compounds, atoms, ions, or clusters of atoms are attached to the outside of the fullerene shell (______________).

Answer 37

exohedral fullerenes

Question 38

Carbon nanotubes are another molecular form of carbon which has recently been discovered that has some unique and technologically promising properties. Its structure consists of a single sheet of graphite (i.e., graphene) that is rolled into a tube; the term __________________ is used to denote this structure.

Answer 38

single-walled carbon nanotube (SWCNT)

Question 39

_______________ carbon nanotubes (MWCNTs) consisting of concentric cylinders also exist

Answer 39

Multiple-walled

Question 40

_____________ are currently being used as reinforcements in polymer-matrix nanocomposites to improve not only mechanical strength, but also thermal and electrical properties.

Answer 40

Bulk nanotubes

Question 41

___________ as the newest member of the nanocarbons, is a single-atomic-layer of graphite, composed of hexagonally sp2 bonded carbon atoms

Answer 41

Graphene

Question 42

# Italicized The first graphene material was produced by peeling apart a piece of graphite, layer by layer using plastic adhesive tape until only a single layer of carbon remained

Answer 42

micromechanical exfoliation or the adhesive-tape method