The formation and characterization of cyclodextrin functionalized polystyrene nanofibers produced by electrospinning.
Polystyrene (PS) nanofibers containing the inclusion complex forming beta-cyclodextrin (beta-CD) were successfully produced by electrospinning aimed at developing functional fibrous nanowebs. By optimization of the electrospinning parameters, which included varying the relative concentration of PS and beta-CD in the solutions, bead-free fibers were produced. Homogeneous solutions of beta-CD and PS in dimethylformamide (DMF) were used with concentrations of PS varying from 10% to 25% (w/v, with respect to DMF), and beta-CD concentrations of 1% to 50% (w/w, with respect to PS). The presence of beta-CD facilitated the production of bead-free PS fibers even from lower polymer concentrations as a result of the higher conductivity of the PS/CD solutions. The morphology and the production of bead-free PS/CD fibers were highly dependent on the beta-CD contents. Transmission electron microscope (TEM) and atomic force microscope (AFM) images showed that incorporation of beta-CD yielded PS fibers with rougher surfaces. Thermogravimetric analysis (TGA) and direct insertion probe pyrolysis mass spectroscopy (DP-MS) results confirmed the presence of beta-CD in the PS fibers. X-ray diffraction (XRD) spectra of the fibers indicated that the beta-CD molecules are distributed within the PS matrix without any phase separated crystalline aggregates up to 40% (w/w) beta-CD loading. Furthermore, chemical analyses by Fourier transform infrared (FTIR) spectroscopy studies confirm that beta-CD molecules are located within the PS fiber matrix. Finally, preliminary investigations using x-ray photoelectron spectroscopy (XPS) and time-of-flight static secondary ion mass spectrometry (ToF-static-SIMS) show the presence of the cyclodextrin molecules in the outer molecular layers of the fiber surfaces. The XPS and ToF-SIMS findings indicate that cyclodextrin functionalized PS webs would have the potential to be used as molecular filters and/or nanofilters for the purposes of filtration/purification/separation owing to surface associated beta-CD molecules which have inclusion complexation capability.
Uyar
Tamer
T
Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Denmark. tamer@inano.dk
Havelund
Rasmus
R
Hacaloglu
Jale
J
Zhou
Xingfei
X
Besenbacher
Flemming
F
Kingshott
Peter
P
D013058:Mass Spectrometry; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D011137:Polystyrenes / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis; D013818:Thermogravimetry; D014783:Viscosity; D047392:beta-Cyclodextrins / Q000737:chemistry*
D011137:Polystyrenes; D047392:beta-Cyclodextrins; C031215:betadex