Chemistry Incompatible with Thermodynamics

[Pentcho Valev]

Countless macroscopic materials reversibly contract and then swell (or vice versa) as the concentration of a chemical agent increases and then decreases:

These materials can obviously do work. Here are two illustrations of how, by concentrating and deconcentrating the chemical agent (hydrogen ions), one can cyclically extract work from pH-sensitive macroscopic polymers able to lift weights:

Figure 4 here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1367611/pdf/biophysj00645-0017.pdf

Figure 16A here: https://pubs.acs.org/doi/pdf/10.1021/jp972167t.

Concentrating and then deconcentrating the chemical agent, per se, consumes no work if done quasistatically, e.g. with the help of a piston permeable to the solvent but impermeable to the chemical agent. In other words, the work lost in concentrating is compensated by the work gained in deconcentrating. Accordingly, in the case of pH-sensitive polymers, lifting the weight is the net work extracted from the cycle. The second law of thermodynamics is clearly violated.

 

[Space Ponder]

Very interesting !

 

[Pentcho Valev]

In his lectures http://www.feynmanlectures.caltech.edu/I_44.html Feynman discusses a non-isothermal heat engine:

https://www.feynmanlectures.caltech.edu/img/FLP_I/f44-01/f44-01_tc_big.svgz

It is impossible to verify whether Feynman's heat engine violates the second law of thermodynamics (has efficiency greater than the Carnot machine) and for that reason it is extremely popular. Thermodynamicists teach it diligently.

There are isothermal analogues which do violate the second law, or at least it is easy to verify this, but thermodynamicists couldn't care less. I have already given examples:

Figure 4 here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1367611/pdf/biophysj00645-0017.pdf

Figure 16A here: https://pubs.acs.org/doi/pdf/10.1021/jp972167t

 

[Pentcho Valev]

Macroscopic pH-sensitive polymers that can do mechanical work, cyclically and isothermally, as hydrogen ions are concentrated and deconcentrated:

Any such cycle clearly violates the second law of thermodynamics if concentrating and deconcentrating occur quasistatically. This could be done by placing the polymer in one of the half-cells here

but it is simpler and more instructive to imagine that the polymer is placed in the solution compartment here (we assume that the membrane is permeable to water but impermeable to the solute, the hydrogen ions):

 

[Pentcho Valev]

"Scientists have developed a special heat-sensitive polymer that's capable of lifting 1,000 times its own weight and quickly contracting back to its original shape." http://www.sciencealert.com/this-new-shape-shifting-polymer-can-lift-1-000-times-its-own-weight

When the temperature varies violations of the second law of thermodynamics are difficult to prove but there are analogous systems where pH-sensitive polymers can do work isothermally (pH changes instead of temperature changes). In isothermal conditions the violation of the second law is almost obvious:

"When the pH is lowered (that is, on raising the chemical potential, μ, of the protons present) at the isothermal condition of 37°C, these matrices can exert forces, f, sufficient to lift weights that are a thousand times their dry weight." http://www.google.com/patents/US5520672

 

[Pentcho Valev]

In the upper picture, a macroscopic polymer contracts and lifts a weight as hydrogen ions in the solution are concentrated (the pH decreases).

Concentrating and then diluting a solute, just like compressing and then expanding a gas, if performed quasistatically and isothermally, involves zero work. Accordingly, lifting the weight is the net work done by the isothermal cycle, in obvious violation of the second law of thermodynamics.