Innovators of Nanoparticle Science
Richard Smalley was a scientist that worked with different allotropes of carbon at Rice University in the late 1900s. He is most well known for his discovery of the first fullerene (C60), one of the most basic allotropes of carbon. An allotrope is basically a different physical form which an element can exist. Before Smalley's discovery, the only 2 known allotropes of carbon were graphite and diamond. Working with Robert Curl and Harold Kroto at a lab at Rice University, he exposed graphite to radiation using a laser and formed a carbon gas which condensed to form carbon spheres made of 60 carbon atoms each. These molecules were named buckminsterfullerenes (fullerenes for short) in honor of Buckminster Fuller who worked with similar shaped geometric objects. This spherical carbon nanoparticle was nicknamed the buckyball and was the first carbon nanoparticle to be discovered. It paved the way for other types of carbon nanoparticles to be discovered, namely single and double walled carbon nanotubes (buckytubes). Smalley, Curl, and Kroto received the Nobel Prize in Chemistry in 1966.
Richard Smalley: The Father of Fullerenes
Sumio Iijima is a Japanese physicist credited for the development of carbon nanotubes, the fourth known allotrope of carbon. There are two types of carbon nanotubes, single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes (MWCNT). MWCNT were discovered first in June of 1991 by Iijima serendipitously while he was observing carbon materials under an electron microscope and found needle-like structures which he dubbed carbon nanotubes. His findings were published in the November edition of the 1991 Nature magazine. Two years later, Iijima discovered the existence of SWCNT in the same laboratory. His findings earned him the 2007 Balzan prize for Nanoscience. These discoveries were monumental and would later show promise in the medical field due to their superior antimicrobial capabilities. In 2007, Iijima's discoveries were applied by Korean scientist Seoktae Kang who published the first article regarding the SWCNT's very effective antimicrobial abilities. Although both SWCNT and MWCNT displayed antimicrobial capabilities, the single walled variant was much more efficient than both MWCNT and fullerenes. Although the reason for this is widely unknown, it is thought that the smaller diameter the single-walled variant leads to higher reactivity with the membrane and causes the cell to lyse.
Sumio Iijima: The Founder of Carbon Nanotubes
