Structure fibrous films

Wu J, Wang N, Wang L, Dong H, Zhao Y, Jiang L (2012) Electrospun porous structure fibrous film with high oil adsorption capacity. ACS Appl Mater Interfaces 4 3207-3212... 

The electrodeposition process investigated for the deposition of PMT occurs in several steps [623-626] (1) nucleation, (2) first monolayer, (3) fibrous film (layer by layer), (4) granular structure. 

Fig. 18.12 (a-f) SEM images and wettability of PU/c-PVA composite fibrous film, (a) Cross section of PU/c-PVA film, which is of two-layer structure, (b, c) PU microfiber layer with high water repellency. (d-f) c-PVA nanofibers layer with hydrophilic property, (g, h) Unidirectional water-penetration phenomenon of the hydrophobic/hydrophilic composite film, (g) Water drops onto the upward hydrophobic PU side and penetrates spontaneously, (h) Water drops onto the upward hydrophilic c-PVA film side and spreads instead of penetration (Reproduced ftom Ref. [45] by permission of The Royal Society of Chemistry)... 

Structure The polymers are produced as powders or as films on the electrodes. Most conductive polymers have a fibrous structure, each fiber consisting of hundreds of strands of polymer molecules. Techniques exist to control fiber preparation so as to obtain nanofibers expected to be particularly useful as catalyst substrates and in electronic applications (MacDiannid, 2000). 

These investigations agree well with experiments by Trillat [129] who found that the X-ray diagram of colloidal nitrocellulose showing a non-oriented structure of crystallites (interference rings), altered after being stretched to indicate a fibrous structure in which the crystallites were oriented along the axis in the direction in which the film was stretched. 

A fibrous specimen was obtained by stretching the swollen film uniaxially (draw ratio 3.5 1). The center of the fiber diagram of the wet, fibrous specimen (Fig. 6A) has a cross-like appearance that suggests a simple helical structure for the molecule. 

In native state, proteins exist as either fibrous or globular form. Protein should be denatured and unfolded to produce an extended chain structure to form film. Extended protein chains can interact through hydrogen, ionic, and hydrophobic bonds to form a three-dimensional stmcture (24). Protein films are excellent gas barriers but poor moisture barriers because of their hydrophilic nature. Mechanical properties and gas permeability depend on the relative humidity (1). Al-ameri (25) smdied the antioxidant and mechanical properties of soy, whey and wheat protein, and carrageenan and carboxymethyl cellulose films with incorporated tertiary-butylhy-droquinone (TBHQ), butylated hydroxytoluene (BHT), fenugreek, and rosemary extracts. Armitage et al. (26) studied egg albumin film as a carrier of natural antioxidants to reduce lipid oxidation in cooked and uncooked poultry. 

Since amylopectin acetate produces only brittle films and plastics, its molecules probably have a non-linear structure which may be branched or coiled. A further striking difference between amylose triacetate and amylopectin triacetate is that the former can be obtained in the form of a highly fibrous mass, whereas the latter occurs only as a fine powder. 

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