Ultrafine fibrous cellulose membranes from electrospinning of cellulose acetate

Abstract

Three solvents, that is, acetone, acetic acid, and dimethylacetamide (DMAc), with a range of solubility parameter ␦, surface tension ␥, viscosity and boiling temperature were used to generate mixtures for electrospinning cellulose acetate (CA) (degree of substitution, DS ϭ 2.45). Although none of these solvents alone enables continuous formation of fibers, mixing DMAc with either acetone or acetic acid produced suitable solvent systems. The 2:1 acetone:DMAc mixture is the most versatile mixture because it allows CA in the 12.5-20% concentration range to be continuously electrospun into fibrous membranes. These CA solutions have between 1.2 and 10.2 poise and ␥ around 26 dyne/cm and produce smooth fibers with diameters from 100 nm to ϳ1 m. Fiber sizes generally decrease with decreasing CA concentrations. The nature of the collectors affects the morphology as well as packing of fibers. Fibers collected on paper have more uniform sizes, smooth surfaces, and fewer defects, whereas fibers collected on water are more varied in size. Electrically conductive solid collectors, such as Al foil and water, favor more tightly packed and less porous membranes. Porous collectors, like paper and copper mesh, produce highly porous membranes. The pores in membranes collected on the Al foil and paper are much better interconnected in the planar directions than those in membranes collected on water. There is evidence that electrospinning induces order in the fibers. Deacetylation of CA membranes is more efficient and complete in NaOH/ethanol than in aqueous NaOH, producing DS values between 0.15 and 2.33 without altering fiber surfaces, packing, or organization. The fully regenerated cellulose membranes are similarly hydrophilic as commodity cellulose fibrous matrices but absorb nearly 10 times as much water.

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“…Cellulose acetate (CA) and its derivatives are the naturally materials resistant to proteolytic degradation suitable to be used as biomedical encapsulating materials [20][21][22][23][24][25] . CA has also been used widely for oral drug coating and encapsulation [26][27][28] .…”

Preparation of Biopolymer Fibers by Electrospinning from Room Temperature Ionic Liquids

“…Cellulose fibers have been made by electrospinning from a variety of solvents such as acetone, acetic acid, and dimethylacetamide. 14 The RTIL, 1-butyl-3-methylimidazolium chloride ([bmIm][Cl]) ( Figure 1) was reported to dissolve up to 25% (w/w) unmodified cellulose with the aid of microwave irradiation. 15 Heparin is a linear, polydisperse, anionic polysaccharide that plays a vital role in regulating many biological activities.…”

Electrospinning Technology for Nanofibrous Scaffolds in Tissue Engineering

“…With increasing viscosity, spherical beads became elongated into spindle-shaped ones, and the number of beads in the structure was reduced. Similarly, Liu et al also reported that a different specific range of viscosity was appropriate for the formation of uniform nanofibers composed of cellulose [49]. In addition, recent studies conducted by Deitzel et al [50] and Demir et al [51] have shown that a more viscous polymer solution resulted in larger fibers.…”