Perpetuum Mobile of the Second Kind Is Commonplace

[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

There are isothermally functioning analogues that obviously violate the second law of thermodynamics:

"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." https://patentimages.storage.googleapis.com/12/1d/09/0fb416e99018cf/US5393602.pdf

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

The upper picture here:

Increasing and then decreasing the concentration of the protons, if done quasistatically, involves, per se, zero net work. Accordingly, lifting the weight is the net work done by the isothermal cycle, in obvious violation of the second law of thermodynamics.

 

[Pentcho Valev]

Any liquid, if placed in an electric field and if no current passes through it, automatically becomes a perpetuum mobile of the second kind. Vigorous jets and flows can appear, able to do mechanical work (e.g. by rotating a waterwheel) at the expense of ambient heat and in violation of the second law of thermodynamics:

View: https://www.youtube.com/watch?v=MUWvQYoPDVg

View: https://www.youtube.com/watch?v=aLcw1fMoc-U&t=112s

View: https://www.youtube.com/watch?v=hr76wCqq_4k


"Is electrospray emission really due to columbic forces?...Columbic forces cannot play a major role in jet formation, even in cases where the liquid consists of a solution of ionic species...Electrospray shows strong analogy with another phenomenon, originally addressed as water bridge: an intense electric field can coax water into leaping a tenths of millimeters gap between two glass beakers, forming a floating bridge." https://aip.scitation.org/doi/10.1063/1.4894800

 

[Pentcho Valev]

The diffusion-through-membrane case is straightforward. If a membrane dividing two compartments is permeable to some solute more in one direction than in the other, and so a concentration difference between the two compartments is created and maintained, then we have a Maxwell's demon type action and a violation of the second law of thermodynamics par excellence.

It seems that such asymmetric membranes are commonplace but authors are too prudent and either don't comment the second-law aspects at all or add absurd calming texts (don't bother, brothers and sisters thermodynamicists, your second law is alive and kicking):

"Diffusion rates through a membrane can be asymmetric, if the diffusing particles are spatially extended and the pores in the membrane have asymmetric structure...In its extreme form, this effect will rapidly seal off flow in one direction through a membrane, while allowing free flow in the other direction. The system thus relaxes to disequilibrium, with very different densities of the permeable species on each side of the membrane." https://arxiv.org/ftp/cond-mat/papers/0412/0412626.pdf

"In biological systems, ion transport across the cell membrane is mostly directional, an embodiment of ionic rectification. Unidirectional ion transport is related to an asymmetric biological nanopore structure, in which the ionic flow in one direction is almost totally suppressed...To realize such extraordinary ion transport properties in technical systems, many nanostructures based on different materials have been fabricated by various techniques, such as asymmetric nanochannels, heterogeneous membranes, and self-assembled two-dimensional materials. The realization of unidirectional ion transport in these examples involves breaking the symmetry of the geometry, surface charge distribution, chemical composition, or channel wall wettability, separately or simultaneously. Despite massive efforts in this field, it is still a challenge to replicate the functionality of biological nanopores and push unidirectional ion transport further for applications. One reason is that ionic rectification in synthetic nanofluidic systems still shows a performance inferior to that of their natural counterparts: The rectification ratio in artificial systems is always on the order of a few hundred while biological systems almost completely suppress the ion diffusion in one direction." https://www.nature.com/articles/s41467-021-24947-3

"Concentration difference is generated internally by a chemically-asymmetric membrane that drives anisotropic diffusion of electrolyte ions, rather than being provided by an external source...This behavior is thermodynamically intriguing. The repeated reversion from pH = 0.00 to pH = - 0.01 indicates a spontaneous sorting of hydrogen ions from a maximum entropy state – one in which [H+] is the same in both chambers – to a lower entropy state, one in which they are 2% different. On its face, this spontaneous reduction in entropy without work input seems at odds with traditional understandings of entropy and the second law [25] but, of course, there is actually no conflict when the entropy changes associated with the walls and membrane are combined with those of the solutions...The pHs and the resultant electrical power appear to be derived from the thermal diffusion of hydrogen ions, hence from purely thermal energy. At first glance this seems at odds with the second law of thermodynamics; however, as specified by the cell half-reactions, the anode continuously grows (precipitating AgCl) at the expense of the cathode, which will eventually disappear and bring the AMCC to a halt. Further investigation of AMCC thermodynamics seems warranted." https://www.sciencedirect.com/science/article/pii/S2213138822002466#b0005

 

[Pentcho Valev]

"As is true of any catalyst, enzymes do not alter the equilibrium point of the reaction. This means that the enzyme accelerates the forward and reverse reaction by precisely the same factor." http://www.columbia.edu/itc/chemistry/ARCHIVE/chem-c2407_f99/problems/kinetics1.pdf

This is an obvious absurdity, and since it is a logical consequence of the second law of thermodynamics, scientists should have applied reductio ad absurdum: Since the consequence is absurd, the underlying premise, the second law of thermodynamics, is false (logic forbids the combination "true premise, absurd consequence"). Examples demonstrating the absurdity of the consequence:

"Interestingly, although [FeFe]-hydrogenases all possess the same active site H cluster, they display a large range of H2 gas oxidation and proton reduction activities, with some displaying a dramatic catalytic bias, that is, the propensity of a catalyst to effect rate of acceleration in one reaction direction over the other. " https://europepmc.org/article/pmc/pmc8653774

"The protein scaffold around an enzyme’s catalytic core exquisitely controls reactivity, including the direction and rate of chemical processes. Scientists refer to this fine tuning as “catalytic bias”—and how it occurs remains widely debated...A research team from three U.S. Department of Energy (DOE) national laboratories and four universities found that subtle changes to the environment surrounding some enzymes can not only change the rate of a cellular reaction by a staggering six orders of magnitude but also its direction. That reversal—the root of the catalytic bias dilemma—is like speeding in one direction at 10 miles-per-second, then going in the opposite direction at 1,000,000 miles-per-second." https://www.pnnl.gov/news-media/remarkable-rate-return-catalytic-bias

"This has resulted in a deeper understanding of the hydrogenase model system and the ability to directly influence catalytic bias. Thus, the work presented here represents key progress towards developing unidirectional catalysts, and demonstrates the possibility of targeted, rational design and implementation of unidirectional catalysts." https://scholarworks.montana.edu/xmlui/handle/1/14621

"However, many enzymes reversibly convert their substrate and product, and if one is interested in catalysis in only one direction, it may be necessary to prevent the reverse reaction...This is the first demonstration, on a specific example, that slowing a step that is rate limiting only when the enzyme works in one direction is a general mechanism for biasing the enzyme in the other direction." https://hal.science/hal-01977597/document

Far from accelerating the forward and backward reactions "by precisely the same factor", in this experiment

Yu Hang Li et al. Unidirectional suppression of hydrogen oxidation on oxidized platinum clusters https://www.nature.com/articles/ncomms3500

the catalyst, PtO, accelerates only 2H+ → H_2, the forward reaction, and SUPPRESSES H_2 → 2H+, the backward reaction:

 

[Pentcho Valev]

"Polymeric artificial muscles are great candidates to replace traditional rigid actuators due to their lightweight nature and high actuation stroke. However, the actuation mechanism of many polymer artificial muscles relies on large temperature changes which may cause polymer degradation...Chemical stimulants, on the other hand, can operate polymer artificial muscles and address these limitations. In this paper, we evaluated the actuation response of athermal pH-responsive artificial muscles...At an actuation stroke of 22 %, the polymer muscle lifts weights over 2000 times heavier relative to its own weight." https://www.sciencedirect.com/science/article/abs/pii/S0925400521002719

"pH-Responsive Hydrogel Composite Artificial Muscle. Here we see a pH-responsive polyacrylic acid hydrogel contained within an unbound carbon fibre braid. The artificial muscle (McKibben style) actuates when placed in a solution with high pH, generating contraction free strains of ~30%."

View: https://www.youtube.com/watch?v=JGn2a21FvLM


Any "athermal" artificial muscle operated by a chemical stimulant is a perpetual motion machine of the second kind. In principle, the concentration of the stimulant can be increased and decreased quasistatically, which means that lifting the weight is the net work done by the isothermal ("athermal") cycle.

Needless to say, artificial muscles are not designed to solve the problems of thermodynamics. The system is open (e.g. acid and alkali are added alternately), processes are far from quasistatical etc.