ORIGINAL CONTRIBUTION Electrospinning and characterization of medium- molecular-weight poly(vinyl alcohol)/high-molecular-weight poly(vinyl alcohol)/montmorillonite nanofibers Hyun Mi Ji & Hyun Woo Lee & Mohammad Rezaul Karim & In Woo Cheong & Eun A. Bae & Tae Hun Kim & Md. Shahidul Islam & Byung Chul Ji & Jeong Hyun Yeum Received: 29 October 2008 / Revised: 15 February 2009 / Accepted: 17 February 2009 / Published online: 3 March 2009 # Springer-Verlag 2009 Abstract Submicron fibers of medium-molecular-weight poly(vinyl alcohol) (MMW-PVA), high-molecular-weight poly(vinyl alcohol) (HMW-PVA), and montmorillonite clay (MMT) in aqueous solutions were prepared by electro- spinning technique. The effect of HMW-PVA and MMT on the morphology and mechanical properties of the MMW- PVA/HMW-PVA/MMT nanofibers were investigated for the first time. Scanning electron microscopy, viscometer, tensile strength testing machine, thermal gravimetric ana- lyzer (TGA), and transmission electron microscopy (TEM) were utilized to characterize the PVA/MMT nanofibers morphology and properties. The MMW-PVA/HMW-PVA ratios and MMT concentration played important roles in nanofiber's properties. TEM data demonstrated that exfoli- ated MMT layers were well distributed within nanofibers. It was also found that the mechanical property and thermal stability were increased with HMW-PVA and MMT contents. Keywords Nanofibers . Poly(vinyl alcohol) . Montmorillonite . Electrospinning Introduction Electrospun polymer nanofibers have attracted a great deal of attention among the academic and industrial scientists because it is a simple and effective technique to produce nanofibers. These electrospun nanofibers have great poten- tial applications to filters, sensors, wound dressing, tissue engineering, drug release, etc. due to unique properties such as high specific surface and narrow diameter [1–8]. Larrondo and Manley first revived the technique by electrostatic spinning of polymer melts in 1981 [9]. Since then, several synthetic and natural polymers were electro- spun into fibers [10]. Recently, scientists take an interest in mechanically and thermally advanced nanofibers with decreasing fiber diameter for many applications. One of the great advantage of this method is to increase nanofibers properties with the incorporation of inorganic materials into polymer nanofibers, and it can exhibit the more advanced properties than homopolymer nanofibers [11–15]. More- over, the properties of the nanofibers are determined by not only the properties of individual fibers but also by the distribution and orientation of the fibers [16]. Montmorillonite (MMT) is one of the most useful inorganic material, and it has been attracting great attention due to its remarkable enhancement in mechanical, thermal, and barrier properties of blend nanofibers with small amounts (1–10 wt.%) of MMT fillers added. Fong et al. first reported the electrospinning of polymer/MMT nanofiber [13]. Hong et al. in their experimental showed that PU/O- MMT nanofiber mats were improved Young's modulus and tensile strength [14]. Li et al. reported that nylon-6/MMT nanofibers have higher melting temperature, Young's modulus, and tensile strength than nylon-6 nanofibers [15]. These property improvements are attributed to the nanometric thickness and high aspect ratio of the individual Colloid Polym Sci (2009) 287:751–758 DOI 10.1007/s00396-009-2019-y H. M. Ji : H. W. Lee : M. R. Karim : M. S. Islam : B. C. Ji : J. H. Yeum (*) Department of Advanced Organic Materials Science and Engineering, Kyungpook National University, Daegu 702-701, South Korea e-mail: jhyeum@knu.ac.kr I. W. Cheong Department of Applied Chemistry, Kyungpook National University, Daegu 702-701, South Korea E. A. Bae : T. H. Kim Department of R&D, Global Challenge Co. Ltd., Daegu 703-833, South Korea