title: Mimicking the Humidity Response of the Plant Cell Wall by Using Two-Dimensional Systems: The Critical Role of Amorphous and Crystalline Polysaccharides.
abstract: Of the composite materials occurring in nature, the plant cell wall is among the most intricate, consisting of a complex arrangement of semicrystalline cellulose microfibrils in a dissipative matrix of lignin and hemicelluloses. Here, a biomimetic, two-dimensional cellulose system of the cell wall structure is introduced where cellulose nanocrystals compose the crystalline portion and regenerated amorphous cellulose composes the dissipative matrix. Spectroscopic ellipsometry and QCM-D are used to study the water vapor uptake of several two-layer systems. Quantitative analysis shows that the vapor-induced swelling of these ultrathin films can be controlled by varying ratios of the chemically identical ordered and unordered cellulose components. Intriguingly, increasing the share of crystalline cellulose appeared to increase the vapor uptake but only in cases for which the interfacial area between the crystalline and amorphous area was relatively large and the thickness of an amorphous overlayer was relatively small. The results show that a biomimetic approach may occasionally provide answers as to why certain native structures exist.
authors.affiliation: Materials Chemistry of Cellulose, Department of Forest Products Technology, Aalto University , 02150 Espoo, Finland.
authors.forename: Elina
authors.initials: E
authors.lastname: Niinivaara
authors.affiliation: UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, Sorbonne Universités , F-75005 Paris, France.
authors.forename: Marco
authors.initials: M
authors.lastname: Faustini
authors.affiliation: VTT - Technical Research Center of Finland, High Performance Fibre Products, 02150 Espoo, Finland.
authors.forename: Tekla
authors.initials: T
authors.lastname: Tammelin
authors.affiliation: Materials Chemistry of Cellulose, Department of Forest Products Technology, Aalto University , 02150 Espoo, Finland.
authors.forename: Eero
authors.initials: E
authors.lastname: Kontturi
mesh_terms: D032701:Biomimetics; D002473:Cell Wall / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry*; D006813:Humidity; D058525:Quartz Crystal Microbalance Techniques; D055682:Viscoelastic Substances / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D055682:Viscoelastic Substances; D014867:Water; D002482:Cellulose