I came across one concept of ‘Polymers with Hidden Length’, which triggered curiosity in me to understand it further. To my surprise, this is not a new phenomenon but one with which we all are living for years and is apparently observed in bones, spider silk, abalone shells, diatoms etc.
Literature defines this ‘Hidden Length’ as a part of the molecule that is constrained from elongating by the sacrificial bond. Here sacrificial bond is described as bonds that break before the breakage of the main molecular structure as these are weaker than them; enabling localized strain relief without chain fracture, therefore increasing its fracture toughness. Thus, hidden length is equivalent to the distance between neighboring sacrificial bonds on one molecule added to the distance between the corresponding binding sites on another polymer molecule.
Some of the recent works in the field:
- Fantner et al. proposed several types of sacrificial bond arrangements and their appearance in a single molecule force spectroscopy measurements, assisting in automated interpretation of pulling curves.
- Elbanna and Carlson investigated the entropic force-elongation behavior of a polymer chain in the sacrificial bond and hidden length system studied in biomaterials such as dentin, whiskers, and mineralized collagen fibrils, and determined it to be proportional to the polymer density.
- Chen and Lu studied methodology to improve toughness of ductile graphene/ polyurethane elastomers with the use of sacrificial bonds and hidden lengths.
- Tian et al. introduced hidden length into polymer chains using a 2,3-diphenylcyclobutene1,4-dicarboxylate into macrocyclic cinnamate dimers.
Dear Readers, do go through the above literature and let me know your viewpoints in the Comments section on the sacrificial bonds and hidden lengths and various application areas it can cater to. Can it have a market and what / when / where / how and why would that be? I believe it can be beneficial in coatings, adhesives, construction, automobile and packaging industries.
Also, if you can, please help me with a query – all polymeric molecules have coiled chain structures, wherein this coiling in between cross-over points can also be called as ‘hidden length’ and can act as pseudo sacrificial bonds?
Dear Readers, do go through the above literature and let me know your viewpoints in the Comments section.
Thanks for reading!
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- Tian, Yancong, et al. “A Polymer with Mechanochemically Active Hidden Length.” Journal of the American Chemical Society 142.43 (2020): 18687-18697.
- Elbanna, Ahmed E., and Jean M. Carlson. “Dynamics of polymer molecules with sacrificial bond and hidden length systems: towards a physically-based mesoscopic constitutive law.” PloS one 8.4 (2013): e56118.
- Fantner, Georg E., et al. “Sacrificial bonds and hidden length: unraveling molecular mesostructures in tough materials.” Biophysical journal 90.4 (2006): 1411-1418.
- Fantner, Georg E., et al. “Sacrificial bonds and hidden length dissipate energy as mineralized fibrils separate during bone fracture.” Nature materials 4.8 (2005): 612-616.
- Lieou, Charles KC, Ahmed E. Elbanna, and Jean M. Carlson. “Sacrificial bonds and hidden length in biomaterials: A kinetic constitutive description of strength and toughness in bone.” Physical Review E 88.1 (2013): 012703.
- Chen, Zhongxin, and Hongbin Lu. “Constructing sacrificial bonds and hidden lengths for ductile graphene/polyurethane elastomers with improved strength and toughness.” Journal of Materials Chemistry 22.25 (2012): 12479-12490.
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