Chain Conformation of Cellulose in a Coordinating Solvent

Hanemann, Otto; Ballauff, M.

doi:10.1021/ma970970f

Cited by 13 publications

(19 citation statements)

References 22 publications

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“…[37 b] The proof for coordinative binding was made by NMR measurements [37 c] and was confirmed by light scattering measurements with some samples. [38] When the complex is bound to the cellulose backbone a characteristic shift of the signals occurs which does not exist in solely solvating solvents.…”

Section: Conformation In Metal Complexing Solventsmentioning

confidence: 99%

Structures of cellulose in solution

Schulz

Seger

Burchard³

2000

Macromol. Chem. Phys.

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Cellulose and their derivatives only rarely form molecularly dispersed solutions. Colloidal aggregates of yet not fully explored supramolecular structure remain preserved even at the highest dilution. The present contribution is concerned with the determination of the number of aggregated chains per colloid particle. In some cases the aggregation number could be directly determined but for the non‐ionic, partial substituted cellulose‐ethers the degree of polymerization of the non‐aggregated cellulose was not sufficiently well known. A detailed analysis of the angular dependencies of scattered light revealed for the large aggregates a star‐shaped structure. The smaller ones were better described by a worm‐like structure. These observations led to the suggestion of a fringed micelle model where several chains are laterally assembled in a rigid stem leaving at both ends coronas of f/2 dangling chains. Recent SANS experiments support this model. The estimated chain length of a single strand was found with DPw = (4–20)×103 much too high and led to the conclusion that 4–20 chains must be co‐linearly (staggered) associated to form one strand. The obtained overall aggregation numbers are close to those found for cellulose in NMMNO and vary from 10 to 800. The similarity of the supramolecular structures in aggregation numbers and dimensions is interpreted as reminiscent of the semi‐crystalline structure of the parental native cellulose fibers. Much lower aggregation numbers were found for cellulose xanthogenates (viscose) in NaOH solution and for cellulose 2.5‐acetate in acetone than for cellulose in NMMNO.

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Section: Conformation In Metal Complexing Solventsmentioning

confidence: 99%

Structures of cellulose in solution

Schulz

Seger

Burchard³

2000

Macromol. Chem. Phys.

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“…Besides electrostatic attraction, the hydrogen bonding between amino groups on the substrate and the hydroxyl groups in the cellulose chain may also contribute to the adsorption of cellulose onto the amino‐mica. It is known that natural cellulose molecule has a large persistent length of ∼10 nm 24. If well solvated, for instance in the good solvent AMIMCl, the cellulose chains should adopt an extended conformation in a dilute solution.…”

Section: Resultsmentioning

confidence: 99%

Capturing the portrait of isolated individual natural cellulose molecules

Wan¹,

Li²,

Cui³

2008

Biopolymers

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Natural cellulose molecules have a strong tendency of being aggregated into larger structures. Thus, the imaging of isolated individual cellulose molecules is hampered for a long time. In this work, we manage to observe, for the first time, the isolated individual natural cellulose chains on a sample surface by means of atomic force microscope. The advantage of the ionic liquid, in which natural cellulose can be molecularly dispersed, is considered to be the key point for the successful imaging. Moreover, we find that the surface charge can influence the morphology of the single cellulose chains upon adsorption. That is, on the positively charged surface, individual cellulose chains adopt an extended conformation; whereas on the negatively charged surface, a compact globule conformation is observed.

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“…Cellulose has broad potential to designing more advanced polymeric materials such as liquid crystalline polymers (Harkness and Gray 1990), welldefined multilayered assemblies (Shaub et al 1993), selective membranes (Hoenich and Stamp 2000), sensor matrixes (Tiller et al 1999), recognition devices (Kubota et al 2001), organic-inorganic complex materials (Hanemann and Ballauff 1997), bioactive and biocompatible materials (Kamitakahara et al 2002) because of its specific structure; strictly linear (1 fi 4)-b-glucan structure and three reactive hydroxyl groups per anhydro glucose unit . One of the interesting attempts is to introduce hydrophobic side chains onto cellulose to yield an amphiphilic polymer that may possibly form a stable monolayer at the air/water interface (Kawaguchi et al 1985).…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of 6-O-(4-stearyloxytrityl)Cellulose acetate Langmuir–Blodgett Films

et al. 2005

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Multilayer films of 2,3-di-O-acetyl-6-O-(4-stearyloxytrityl)cellulose (ASTC) were prepared and investigated. The fairly high surface pressure (p)-area (A) isotherms (36-47 mN/m) suggest that the balky and hydrophobic trityl group contribute to form a condensed monolayer. The cellulose derivative formed a homogeneous monolayer at 10 mN/m. The monolayer on the water surface was transferred successfully at 10 mN/m onto various substrates by modifying the preparation methods, to form Z-type multilayer films. The ultraviolet-visible (UV-Vis) absorbance was independent of the number of layers, indicating that each layer is made of definite number of anhydroglucose unit (AGU). The monolayer thickness determined from atomic force microscope (AFM) and ellipsometry was calculated to be about 1.9 nm, suggesting that the long alkyl chain in the film has a so-called hairy-rod type structure. This is the first paper about the Z-type LB film prepared from cellulose derivatives having long mono-alkyl chain only at 6-O-position.

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Chain Conformation of Cellulose in a Coordinating Solvent

Cited by 13 publications

References 22 publications

Structures of cellulose in solution

Structures of cellulose in solution

Capturing the portrait of isolated individual natural cellulose molecules

Preparation and Characterization of 6-O-(4-stearyloxytrityl)Cellulose acetate Langmuir–Blodgett Films

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