Chemistry · Ch 16 — Green Chemistry and Nanochemistry
Introduction to Nanochemistry
Introduction to Nanochemistry
From the clothes and sunglasses people wear to computer hard drives and everyday cleaning products, nanotechnology plays a significant role in the manufacture of a huge range of materials -- lasers used in CD and DVD players, for instance, have long contained nanosized components without most users ever realising it. Two comparative figures set the scale for the whole topic. Figure 16.1 lays out a size scale running from macro-materials down to individual atoms -- from an ant (about 5 mm) and a dust mite (about 200 micrometres), through human hair (10-50 micrometres wide) and red blood cells (2-5 micrometres wide), down to a carbon nanotube (about 2 nm in diameter) and DNA (2-12 nm in diameter), ending at the atomic scale itself, illustrated by a quantum corral of 48 iron atoms individually positioned on a copper surface using a scanning tunnelling microscope tip (a 14 nm corral diameter). Figure 16.2 complements this with materials found in nature alongside man-made devices at comparable scales. Across both figures, some objects -- a tennis ball, an ant, human hair -- are large enough to see with the naked eye, while others -- bacteria, viruses, red blood cells -- cannot be seen without instrumentation; it is this second group, the objects too small to see unaided, that are generally referred to as nanomat …
What this figure shows. A vertical size-scale diagram running from centimetre scale down through millimetre, micrometre and nanometre/angstrom scale (the scale's own printed powers-of-ten labels appear slightly inconsistent between two adjacent rows in the source, which this platform flags rather than silently correcting, since the qualitative scale -- centimetres down to nanometres -- is unambiguous). Real-world objects are placed at their matching point on this scale: an ant at about 5 mm, a dust mite at about 200 micrometres, human hair at 10-50 micrometres wide, red blood cells at 2-5 micrometres wide, DNA at 2-12 nm diameter, a carbon nanotube at about 2 nm diameter, microelectromechanical devices at 10-100 micrometres, and -- at the very bottom of the scale -- a quantum corral of 48 iron atoms positioned one at a time on a copper surface with a scanning tunnelling microscope tip, with a corral diameter of 14 …
What this figure shows. A companion figure to Fig 16.1, depicting materials found in nature alongside devices that are man-made, arranged so their relative sizes can be compared directly against each other and against the numeric size scale of Fig 16.1. As in Fig 16.1, some of the depicted objects (such as an ant or human hair) are large enough to be seen with the naked eye, while others (bacteria, viruses, red blood cells) are not, and it is specifically this class of naked-eye-invisible objects at t …