title: Ferrocene-decorated nanocrystalline cellulose with charge carrier mobility.
abstract: Ferrocene-decorated cellulose nanowhiskers were prepared by the grafting of ethynylferrocene onto azide functionalized cotton-derived cellulose nanowhiskers using azide-alkyne cycloaddition. Successful surface modification and retention of the crystalline morphology of the nanocrystals was confirmed by elemental analysis, inductively coupled plasma-atomic emission spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The coverage with ferrocenyl is high (approximately 1.14 × 10(-3) mol g(-1) or 4.6 × 10(13) mol cm(-2) corresponding to a specific area of 61 Å(2) per ferrocene). Cyclic voltammetry measurements of films formed by deposition of ferrocene-decorated nanowhiskers showed that this small spacing of redox centers along the nanowhisker surface allowed conduction hopping of electrons. The apparent diffusion coefficient for electron (or hole) hopping via Fe(III/II) surface sites is estimated as Dapp = 10(-19) m(2)s(-1) via impedance methods, a value significantly less than nonsolvated ferrocene polymers, which would be expected as the 1,2,3-triazole ring forms a rigid linker tethering the ferrocene to the nanowhisker surface. In part, this is believed to be also due to "bottleneck" diffusion of charges across contact points where individual cellulose nanowhiskers contact each other. However, the charge-communication across the nanocrystal surface opens up the potential for use of cellulose nanocrystals as a charge percolation template for the preparation of conducting films via covalent surface modification (with applications similar to those using adsorbed conducting polymers), for use in bioelectrochemical devices to gently transfer and remove electrons without the need for a solution-soluble redox mediator, or for the fabrication of three-dimensional self-assembled conducting networks.
authors.affiliation: School of Chemistry, University of Nottingham , University Park, Nottingham NG7 2RD, United Kingdom.
authors.forename: Samuel
authors.initials: S
authors.lastname: Eyley
authors.forename: Sara
authors.initials: S
authors.lastname: Shariki
authors.forename: Sara E C
authors.initials: SE
authors.lastname: Dale
authors.forename: Simon
authors.initials: S
authors.lastname: Bending
authors.forename: Frank
authors.initials: F
authors.lastname: Marken
authors.forename: Wim
authors.initials: W
authors.lastname: Thielemans
mesh_terms: D002482:Cellulose / Q000138:chemical synthesis / Q000737:chemistry*; D003500:Cyclization; D055664:Electrochemical Techniques; D005296:Ferrous Compounds / Q000737:chemistry*; D000075163:Metallocenes; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D005296:Ferrous Compounds; D000075163:Metallocenes; D002482:Cellulose; C004998:ferrocene