title: Counterion Size and Nature Control Structural and Mechanical Response in Cellulose Nanofibril Nanopapers.
abstract: Nanopapers formed from aqueous dispersions of cellulose nanofibrils (CNFs) combine stiffness, strength, and toughness. Yet, delicate interactions operate between the CNFs during nanopaper formation and mechanical deformation. We unravel in detail how counterions, being either of the organic alkyl ammonium kind (NR4+) or of the earth metal series (Li+, Na+, Cs+), need to be chosen to achieve outstanding combinations of stiffness, strength, and toughness, extending to previously unreached territories. We relate structure formation processes in terms of colloidal stabilization to nanostructural details such as porosity and ability for swelling, as well as to interfibrillar interactions in bulk and macroscale mechanical properties. We demonstrate that our understanding also leads to new levels of ductility in bioinspired CNF/polymer nanocomposites at high levels of reinforcements. These results contribute to future rational design of CNF-based high-performance materials.
authors.affiliation: Institute for Macromolecular Chemistry, Albert-Ludwigs-University Freiburg , Stefan-Meier-Straße 31, 79104 Freiburg, Germany.|Freiburg Materials Research Center, Albert-Ludwigs-University Freiburg , Stefan-Meier-Straße 21, 79104 Freiburg, Germany.|Freiburg Center for Interactive Materials and Bioinspired Technologies, Albert-Ludwigs-University Freiburg , Georges-Köhler-Allee 105, 79110 Freiburg, Germany.
authors.forename: Alejandro J
authors.initials: AJ
authors.lastname: Benítez
authors.affiliation: Institute for Macromolecular Chemistry, Albert-Ludwigs-University Freiburg , Stefan-Meier-Straße 31, 79104 Freiburg, Germany.|Freiburg Materials Research Center, Albert-Ludwigs-University Freiburg , Stefan-Meier-Straße 21, 79104 Freiburg, Germany.|Freiburg Center for Interactive Materials and Bioinspired Technologies, Albert-Ludwigs-University Freiburg , Georges-Köhler-Allee 105, 79110 Freiburg, Germany.
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0003-2170-3306
authors.initials: A
authors.lastname: Walther
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives*; D003102:Colloids / Q000737:chemistry; D055595:Mechanical Phenomena; D008672:Metals, Alkali / Q000737:chemistry; D057139:Nanofibers / Q000737:chemistry*; D010209:Paper; D013499:Surface Properties
chemical_list: D003102:Colloids; D008672:Metals, Alkali; D002482:Cellulose