Nanodomains of I_α and I_β Cellulose in Algal Microfibrils

Abstract

Ultrastructural localization of cellulose Iα and Iβ allomorphs in one microfibril from algal sources was investigated using electron microdiffraction. Both cellulose Iα and Iβ were characterized as one-chain triclinic and two-chain monoclinic unit cells, respectively, in agreement with previous studies. These two structures coexisted in each microfibril, alternating either longitudinally or laterally. The transition zone between the two phases was found to be the interface between adjacent H-bonded molecular sheets (i.e., 0.39-nm lattice planes).

Structural Evolution of Gossypium hirsutum Fibers Grown under Greenhouse and Hydroponic Conditions

“…No band is found at 710 cm −1 and thus an assignment to one of the possible cellulose allomorphs using FT-IR ATR is not possible. This is in opposition to the previous assumption that these bands are characteristic of I β (monoclinic, 710 cm −1 ) and I α (triclinic, 750-760 cm −1 ) and cannot be used for this purpose [23][24][25]. Using other characterization techniques than FT-IR ATR, the fibers from cotton grown under hydroponic/greenhouse conditions have been classified as cellulose I β (monoclinic) [7].…”

Conversion of cellulose Iα to Iβ via a high temperature intermediate (I-HT) and other cellulose phase transformations

“…Cellulose Ia and Ib differ mainly in the stacking arrangement of hydrogen bonded layers, with Ia layers always displaced along the molecular axis by ?c/4, whereas hydrogen bonded layers in cellulose Ib alternate between ?c/4 and -c/4 displacement Imai and Sugiyama 1998;Nishiyama et al 2002;Nishiyama et al 2003). This alternating layer arrangement in Ib makes half of the inter-layer interactions identical to those in Ia.…”

“…A single anti conformation of a glycosidic linkage in a cellulose chain would produce a 180°rotation of the chain. Alternation between Ia and Ib packing along single microfibrils at *50 nm length scale has been observed, which may be partly explained by occasional chain breaks, or by these unusual conformations of the glycosidic linkage Debzi et al 1991;Imai and Sugiyama 1998).…”

In situ X-ray diffraction investigation of thermal decomposition of wood cellulose

“…The elementary cellulose microfibrils are aligned parallel to each other and wind around the wood cell in a helical manner at a characteristic microfibril angle with respect to the cell axis [1,3,4]. Native crystalline cellulose (cellulose I) has been intensively studied in polymer science for almost one century [5][6][7][8][9][10]. Two polymorphs of cellulose I exist, triclinic cellulose Iα and monoclinic cellulose Iβ.…”