title: Sacrificial bonds and hidden length: unraveling molecular mesostructures in tough materials.
abstract: Sacrificial bonds and hidden length in structural molecules and composites have been found to greatly increase the fracture toughness of biomaterials by providing a reversible, molecular-scale energy-dissipation mechanism. This mechanism relies on the energy, of order 100 eV, needed to reduce entropy and increase enthalpy as molecular segments are stretched after being released by the breaking of weak bonds, called sacrificial bonds. This energy is relatively large compared to the energy needed to break the polymer backbone, of order a few eV. In many biological cases, the breaking of sacrificial bonds has been found to be reversible, thereby additionally providing a "self-healing" property to the material. Due to the nanoscopic nature of this mechanism, single molecule force spectroscopy using an atomic force microscope has been a useful tool to investigate this mechanism. Especially when investigating natural molecular constructs, force versus distance curves quickly become very complicated. In this work we propose various types of sacrificial bonds, their combination, and how they appear in single molecule force spectroscopy measurements. We find that by close analysis of the force spectroscopy curves, additional information can be obtained about the molecules and their bonds to the native constructs.
authors.affiliation: Department of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, USA. fantner@physics.ucsb.edu
authors.forename: Georg E
authors.initials: GE
authors.lastname: Fantner
authors.forename: Emin
authors.initials: E
authors.lastname: Oroudjev
authors.forename: Georg
authors.initials: G
authors.lastname: Schitter
authors.forename: Laura S
authors.initials: LS
authors.lastname: Golde
authors.forename: Philipp
authors.initials: P
authors.lastname: Thurner
authors.forename: Marquesa M
authors.initials: MM
authors.lastname: Finch
authors.forename: Patricia
authors.initials: P
authors.lastname: Turner
authors.forename: Thomas
authors.initials: T
authors.lastname: Gutsmann
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Morse
authors.forename: Helen
authors.initials: H
authors.lastname: Hansma
authors.forename: Paul K
authors.initials: PK
authors.lastname: Hansma
mesh_terms: D053674:Aggrecans; D000538:Aluminum Silicates / Q000737:chemistry; D001696:Biomechanical Phenomena; D011508:Chondroitin Sulfate Proteoglycans / Q000737:chemistry*; D003198:Computer Simulation; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D005983:Glutens / Q000737:chemistry*; D006820:Hyaluronic Acid / Q000737:chemistry*; D006860:Hydrogen Bonding; D037181:Lectins, C-Type / Q000737:chemistry*; D008956:Models, Chemical
chemical_list: D053674:Aggrecans; D000538:Aluminum Silicates; D011508:Chondroitin Sulfate Proteoglycans; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D005983:Glutens; D006820:Hyaluronic Acid; C011934:mica