Nanomaterials: Properties, Preparation and Applications - Environmental and Human Health Impacts of Nanotechnology - page 31

2.2 Introduction

There have been several debates over what constitutes a nanomaterial and what
defi nes nanotechnology, as discussed in Chapter 1. However, aside from this, there
is no doubt that the area has seen massive growth over the past few decades. The
relative percentages of publications containing the key phrases 'synthesis of nano-
materials' , ' nanotechnology ' and ' nanoscience ' are shown in Figures 2.1 and 2.2.
Overall these fi gures show that nanotechnology itself predates the use of the term
in the scientifi c literature, as the ability to prepare commercial nanostructured
materials, such as zeolites, dates from 1956 and the interest in preparing sols of
nanoparticles dates as far back as Faraday. Figure 2.2 gives some indication regard-
ing the rates of growth and sizes of some high profi le areas in nanotechnology.
It clearly shows that some of the words being used to describe current technology
have only been used in the scientifi c literature for a few years.
The recent increase in interest in nanotechnology and nanomaterials and its
tentative application in consumer products has led to the realisation that clear
defi nitions are needed so that communication across the broad range of disciplines
involved may be transparent and easily understood. Furthermore, for regulation to
be conceived defi nitions are required so that regulation may be enforced. Currently
the use of size as a defi nition of a nanoparticle is common and follows the similar
application of size in the defi nition of the ultrafi ne particle in atmospheric science.
The latter have been of interest for a number of years, mainly in relation to inhala-
tion exposure in humans and air pollution. However, many of these nanomaterials

30

25

Synthesis of nanomaterials (50670)
Nanotechnology (5248)
Nanoscience (596)

20

15

10

5

0

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Year

Figure 2.1 The number of publications with key terms in their title or abstract. (Source;
MIMAS Web of Science.)