Werner Kuhn (February 6, 1899 – August 27, 1963) was a Swiss
physical chemist
Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical me ...
who developed the first model of the
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
of polymer solutions using
statistical mechanics
In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. It does not assume or postulate any natural laws, but explains the macroscopic be ...
.
[Werner Kuhn]
- Encyclopædia Britannica He is known for being the first to apply
Boltzmann's entropy formula
In statistical mechanics, Boltzmann's equation (also known as the Boltzmann–Planck equation) is a probability equation relating the entropy S, also written as S_\mathrm, of an ideal gas to the multiplicity (commonly denoted as \Omega or W), the ...
:
:
to the modeling of
rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...
molecules, i.e. the "rubber band
entropy
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
model",
molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...
s which he imagined as chains of ''N'' independently oriented links of length ''b'' with an end-to-end distance of ''r''. This model, which resulted in the derivation of the thermal
equation of state
In physics, chemistry, and thermodynamics, an equation of state is a thermodynamic equation relating state variables, which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature, or internal ...
of rubber, has since been extrapolated to the
entropic
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
modeling of proteins and other conformational polymer chained molecules attached to a surface.
Kuhn received a degree in
chemical engineering
Chemical engineering is an engineering field which deals with the study of operation and design of chemical plants as well as methods of improving production. Chemical engineers develop economical commercial processes to convert raw materials int ...
at the Eidgenössische Technische Hochschule (ETH,
Federal Institute of Technology
(colloquially)
, former_name = eidgenössische polytechnische Schule
, image = ETHZ.JPG
, image_size =
, established =
, type = Public
, budget = CHF 1.896 billion (2021)
, rector = Günther Dissertori
, president = Joël Mesot
, a ...
), in Zürich, and later a doctorate (1923) in
physical chemistry
Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mecha ...
. He was appointed professor of physical chemistry at the University of Kiel (1936–39) and then returned to Switzerland as director of the Physico-Chemical Institute of the
University of Basel
The University of Basel (Latin: ''Universitas Basiliensis'', German: ''Universität Basel'') is a university in Basel, Switzerland. Founded on 4 April 1460, it is Switzerland's oldest university and among the world's oldest surviving universit ...
(1939–63), where he also served as rector (1955–56).
In a 1951 lecture along with his student V.B. Hargitay, he was the first to hypothesize the
countercurrent multiplier mechanism in the mammalian kidney, later to be discovered in many other similar biological systems.
[A 200]
translation of the 1951 lecture originally published in German
The translation was published with remarks by Professor Bart Hargitay, then one of Kuhn's two former student aids. Harbitay says: Before settling in Basel, Kuhn did some very fundamental work in Kiel, separating isotopes in a centrifuge. This caused him to be fascinated with the effect of countercurrents in multiplying a very small single effect to significant separations. (Journal of the American Society of Nephrology website)
See also
*
Kuhn length
The Kuhn length is a theoretical treatment, developed by Hans Kuhn, in which a real polymer chain is considered as a collection of N Kuhn segments each with a Kuhn length b. Each Kuhn segment can be thought of as if they are freely jointed with ...
References
External links
* Hirsch, Warren (2003).
Disorder in un-stretched rubberbands, ''JCE, February Vol. 80'', No. 2, p. 145
{{DEFAULTSORT:Kuhn, Werner
Thermodynamicists
1899 births
1963 deaths
Swiss physical chemists