While electrospinning has been widely employed to spin nanofibers, its low production rate has limited its potential for industrial applications. Comparing with electrospinning, centrifugal spinning technology is a prospective method to fabricate nanofibers with high productivity. In the current study, key parameters of the centrifugal spinning system, including concentration, rotational speed, nozzle diameter and nozzle length, were studied to control fiber diameter. An empirical model was established to determine the final diameters of nanofibers via controlling various parameters of the centrifugal spinning process. The empirical model was validated via fabrication of carboxylated chitosan (CCS) and polyethylene oxide (PEO) composite nanofibers. DSC and TGA illustrated that the thermal properties of CCS/PEO nanofibers were stable, while FTIR-ATR indicated that the chemical structures of CCS and PEO were unchanged during composite fabrication. The empirical model could provide an insight into the fabrication of nanofibers with desired uniform diameters as potential biomedical materials. This study demonstrated that centrifugal spinning could be an alternative method for the fabrication of uniform nanofibers with high yield.

Poly(vinyl chloride) membranes were prepared via a phase inversion method, using N,N-dimethylacetamide (DMAc) as solvent, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and sucrose as three typical additives and water as the coagulation medium. The phase diagrams of the PVC/DMAc/additives/water quaternary systems were constructed using cloud-point experimental data. With the addition of the different additives, the effect of dope solution temperature on the dope solution viscosity and the structure of membranes were investigated. It indicates that the viscosity of the PVC/DMAc dope solution with the additive increase compared with the dope solution without any additive and the addition of the additives into the dope solution alter the morphology and structure of the resultant membranes during the phase-inversion process.

Nanofibrous biomaterials have huge potential for drug delivery, due to their structural features and functions that are similar to the native extracellular matrix (ECM). A wide range of natural and polymeric materials can be employed to produce nanofibrous biomaterials. This review introduces the major natural and synthetic biomaterials for production of nanofibers that are biocompatible and biodegradable. Different technologies and their corresponding advantages and disadvantages for manufacturing nanofibrous biomaterials for drug delivery were also reported. The morphologies and structures of nanofibers can be tailor-designed and processed by carefully selecting suitable biomaterials and fabrication methods, while the functionality of nanofibrous biomaterials can be improved by modifying the surface. The loading and releasing of drug molecules, which play a significant role in the effectiveness of drug delivery, are also surveyed. This review provides insight into the fabrication of functional polymeric nanofibers for drug delivery.

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Poly(vinyl chloride) (PVC)/polyacrylonitrile (PAN) blend hollow-fiber membranes were prepared by a phase-inversion method with water as inner and outer coagulations. The influence of the compatibility of the two polymers on the formation of interfacial microvoids (IFMs) in the PVC/PAN blend hollow-fiber membranes was investigated by the theory of thermodynamics and examined by Fourier transform infrared spectroscopy, dynamic mechanical analysis, viscometry, and scanning electron microscopy. All of the results show that good compatibility did not exist in the PVC/PAN blend systems; this led to the formation of IFMs between the two polymers. Also, the performance of the experimental results showed that the addition of PAN contributed to the enhancement of the permeability of the blend membranes; this laid the foundation for further study of PVC/ PAN blend hollow-fiber membranes with antifouling properties after hydrolysis. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124: E9-E16, 2012