Electrospinning water soluble polymers

Polyaniline-based nanofibers with diameter below 30 nm were obtained with the electrospinning process [304] which is suitable not only for conjugated polymers, but also for non conjugated, water soluble polymers such as poly-ethylen oxide (PEO), polyvinyl alcohol (PVA) and poly-lactic acid (PLA). In fact, one of the... 

These considerations encouraged water-soluble polymers such as PEO to be popularly studied in early research on electrospinning. Only limited work on electrospinning of polymers such as polyamides was reported in the early literature because of the requirement for expensive and/or hazardous solvents (e.g., formic acid for nylon-6,6). 

Mincheva, R., N. Manolova, D. Paneva, and I. Rashkov (2005). Preparation of polyelectrolyte-containing nanofibers by electrospinning in the presence of a non-ionogenic water-soluble polymer. Journal of Bioactive and Compatible Polymers 20(5) 419-435. 

Besides water-soluble polymers, more synthetic polymers are insoluble in water and should be dissolved in organic solvent for electrospinning, such as polylactic-co-glycolic acid (PLLA), PCL, polybutylene succinate-co-butylene terephthalate (PBST), polyhydroxyalkanoates (PHA), polybutylene succinate (PBS), PAN, poly-sulfone (PSF), polyimide (PI), polyethylene-co-vinyl alcohol (PEVA), PU, polypyrrole (PPy), polyoxymethylene (POM), PS, polymethyl methacrylate (PMMA), PVC, polyvinylidene fluoride (PVDF), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), poly A-vinylcarbazole (PVK), polymeta-phenylene isophthalamide (PMIA), polyethylene terephthalate (PET), polycarbonate (PC), polybenzimidazole (PBI), polymer vinyl acetate (PVAc), polyvinyl butyral (PVB), and polyethylene-co-vinyl acetate (PEV). 

Various polymers have been successfully electrospun from solution, sol-gel suspension, or melt into ultrafine nanotibers. For example, as listed in Table 13.2, these polymers included nylon-6 [20, 21], polyacrylonitrile (PAN) [22, 23], polyethylene terephthalate (PET) [24], polyvinyl alcohol (PVA) [25], polystyrene (PS) [26, 27], polyvinylidene fluoride (PVDF) [28, 29], polyethersulfone (PES) [30], polyimides (PI) [31, 32], polyethylene oxide (PEO) [33], polyurethanes (PU) [34], polycarbonates (PC) [35], polycaprolactone (PCL) [36], polybenzimidazole (PBI) [37, 38], polyvinylpyrrolidone (PVP) [39], polytrimethylene terephthalate (PTT) [40], polyvinyl chloride (PVC) [41], polymethylmethacrylate (PMMA) [42], hydrox-ypropyl cellulose (HPC) [43], polyglycolic acid (PGA) [44], polyhydroxybutyrate (PHB) [45], cellulose acetate (CA) [46,47] and many more. To be used as filtration membranes, nanoflbers made of water-soluble polymers have to be further cross-linked after the electrospinning process. As polymers having different physical and... 

As reported in other chapters in this volume, PLA is one of the most used materials for biomedical applications due to biocompatibility and biodegradability, but hydrophobic properties require the encapsulation of water-soluble agents to avoid decomposition and failure of the polymer as a drug-carrier substrate. One of the advantages of coaxial electrospinning is that solid or liquid drugs can be incorporated into electrospun nanofibres and it is possible to encapsulate drugs into a structural shell. 

Carboxymethyl chitosan (CM chitosan) is another water soluble chitosan derivative produced by the substitution of the -OH of chitosan by -CH2COOH. CM chitosan shows high viscosity, large hydrodynamic volume as well as biocompatibility. CM chitosan requires another polymer such as PVA, PEO, or PAA to form fibers by electrospinning [192]. Nanofibers with an average diameter of 130 nm were obtained from CM chitosan/PVA blends and finther cross-linking makes the fiber mats water-insoluble. 

---