title: Nanostructured artificial nacre.
abstract: Finding a synthetic pathway to artificial analogs of nacre and bones represents a fundamental milestone in the development of composite materials. The ordered brick-and-mortar arrangement of organic and inorganic layers is believed to be the most essential strength- and toughness-determining structural feature of nacre. It has also been found that the ionic crosslinking of tightly folded macromolecules is equally important. Here, we demonstrate that both structural features can be reproduced by sequential deposition of polyelectrolytes and clays. This simple process results in a nanoscale version of nacre with alternating organic and inorganic layers. The macromolecular folding effect reveals itself in the unique saw-tooth pattern of differential stretching curves attributed to the gradual breakage of ionic crosslinks in polyelectrolyte chains. The tensile strength of the prepared multilayers approached that of nacre, whereas their ultimate Young modulus was similar to that of lamellar bones. Structural and functional resemblance makes clay- polyelectrolyte multilayers a close replica of natural biocomposites. Their nanoscale nature enables elucidation of molecular processes occurring under stress.
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Tang
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Kotov
authors.forename: Sergei
authors.initials: S
authors.lastname: Magonov
authors.forename: Birol
authors.initials: B
authors.lastname: Ozturk
mesh_terms: D000538:Aluminum Silicates / Q000138:chemical synthesis / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry; D040761:Biomimetic Materials / Q000138:chemical synthesis* / Q000737:chemistry; D018786:Bone Substitutes / Q000138:chemical synthesis / Q000737:chemistry*; D000077215:Clay; D004548:Elasticity; D004573:Electrolytes / Q000138:chemical synthesis / Q000737:chemistry*; D046911:Macromolecular Substances; D008420:Manufactured Materials; D008422:Materials Testing / Q000379:methods; D018625:Microscopy, Atomic Force; D008974:Mollusca / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D013312:Stress, Physiological; D013718:Tensile Strength
chemical_list: D000538:Aluminum Silicates; D001672:Biocompatible Materials; D018786:Bone Substitutes; D004573:Electrolytes; D046911:Macromolecular Substances; D000077215:Clay