Hydrocarbon Processing - July 2022 - 43

History of the HPI
possible without the advancement of liquid
crystal polymers technology.
Although first discovered in the late
1800s by Austrian botanist and chemist
Friedrich Reinitzer, liquid crystals did
not find commercial success until nearly
100 yr later. In the late 1880s, Reinitzer
was experimenting with cholesteryl benzoate.
While heating the organic chemical,
he noticed that it changed from a white
solid to a hazy liquid, which then turned
clear at higher temperatures. According
to literature, Reinitzer observed that the
liquid passed through two different color
forms before returning to the original
white solid form. Reinitzer concluded
that the substance passed through two different
melting points, which should not
exist-German chemist Wilhelm Heintz
observed the same phenomenon while
conducting similar experiments on fatty
acids in the mid-1850s.194
Reinitzer sent his findings to German
physicist Otto Lehmann. Upon heating
the material, Lehmann viewed the reaction
under a microscope. As the solid changed
into a milky liquid, Lehmann observed
multiple small crystalline formations with
irregular borders.194
the advancement of liquid crystals
technologies research.
* Richard Williams and George
Heilmeier: Their work at RCA
Laboratories in the U.S. in
1962 were the origins of using
a liquid crystal-based flat panel
display to replace the cathode ray
vacuum tube used in televisions.
However, to be used effectively,
the compound used in the process
(para-azoxyanisole) to create a
nematic liquid crystal state required
too high of a temperature (> 116°C)
to make it a practical application
for television displays. In 1966,
while working within the Heilmeier
group, Scientists Joel Goldmacher
and Joseph Castellano were able
to create nematic liquid crystals at
room temperature by altering the
compounds used in the process.
This enabled RCA to produce the
first practical display device.
In 1972, George Gray and Ken HarAfter
additional testing
and review, Lehmann believed this phase
was a new state of matter, one between a
solid and a liquid. He named the substance
liquid crystals and published his findings
" About floating crystals " in Zeitschrift für
Physikalische Chemie (Journal of Physical
Chemistry) in 1889. This was the first publication
on liquid crystals.195
However, no commercial applications
were discovered using liquid crystals. It
was not until the late 1940s that extensive
research began to be conducted on liquid
crystals applications for commercial endeavors.
This included works from the following
references described in literature:196
* English researcher George William
Gray: His book Molecular Structure
and the Properties of Liquid Crystals
provided a detailed understanding
on designing molecules that exhibit
the liquid crystalline state. His
work would be instrumental in the
future adoption of liquid-crystal
displays (LCDs).
* American chemist Glenn H. Brown:
His liquid crystals conference
in the mid-1960s gathered the
world's most-prominent scientists
on the subject and was a catalyst
for worldwide research efforts on
rison worked with the Royal Radar
Establishment in Malvern, England to
produce stable liquid crystals for small
LCDs within electronic products.196
Additional
research in the 1980s led to an
extensive use of liquid crystal polymers
in display devices (i.e., LCDs for television,
mobile phones, personal computers
and laptops) and other products within
the automotive, electronics and medical
sectors. Today, many companies produce
liquid crystal polymers (e.g., Celanese,
Polyplastics, Solvay, Sumitomo Chemicals
and Toray Industries), and forecasts
show the liquid crystals polymers market
to reach nearly $2.5 B by 2030.197
Conducting polymers. Prior to the
1970s, it was a common belief that plastics
could not conduct electricity. However,
research by three scientists changed
the fundamental thought on the conductivity
of polymers. This research would
not only lead to the production of many
different products for various industries,
but also earned these men the Nobel Prize
in Chemistry.
Conductive polymers are organic polymers
that conduct electricity.198
Research
and discovery of partly conductive polymers
date back to 1862. While working at
the College of London Hospital, English
chemist Henry Letheby obtained a partlyconductive
material by anodic oxidation
of aniline in sulfuric acid.199
Additional research
in the 1970s found that polythiazyl
(polymeric sulfur nitrade) was superconductive
at low temperatures, while several
other conductive organic compounds were
superconductive at high temperatures.199
In the early 1970s, Japanese chemist
and engineer Hideki Shirakawa led a group
that adapted Ziegler-Natta polymerization
to produce well-defined, silvery films of
polyacetylene (the work of Karl Ziegler
and Giulio Natta is detailed in the History
of the HPI section of the April issue).199,200
During the same timeframe, American
physicist Alan Heeger and New Zealandborn
American chemist Alan MacDiarmid
were researching the metallic properties
of polythiazyl. The two scientists shifted
their focus to polyacetylene after MacDiarmid
met with Shirakawa in Tokyo.
In 1976, MacDiarmid, Shirakawa and
Heeger (FIG. 3) collaborated on additional
research focused on the conductivity
of polyacetylene. In 1977, additional
FIG. 3. MacDiarmid, Shirakawa and Heeger were awarded the Nobel Prize in Chemistry in 2000
for their work on conductive polymers. Photo courtesy of the Nobel Foundation archives.
Hydrocarbon Processing | JULY 2022 43

Hydrocarbon Processing - July 2022

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