Controlled Morphology of Porous Polyvinyl Butyral Nanofibers

Daniela Lubasova,Lenka Martinova

doi:10.1155/2011/292516

Abstract

A simple and effective method for the fabrication of porous nanofibers based on the solvent evaporation methods in one-step electrospinning process from the commercial polyvinyl butyral (PVB) is presented. The obtained nanofibers are prevalently amorphous with diameters ranging from 150 to 4350 nm and specific surface area of approximately 2–20 m2/g. Pore size with irregular shape of the porous PVB fibers ranged approximately from 50 to 200 nm. The effects of polymer solution concentration, composition of the solvents mixture, and applied voltage on fiber diameter and morphology were investigated. The theoretical approach for the choice of poor and good solvents for PVB was explained by the application Hansen solubility parameter (HSP) and two-dimensional graph. Three basic conditions for the production of porous PVB nanofibers were defined: (i) application of good/poor solvent mixture for spinning solution, (ii) differences of the evaporation rate between good/poor solvent, and (iii) correct ratios of good/poor solvent (v/v). The diameter of prepared porous PVB fibers decreased as the polymer concentration was lowered and with higher applied voltage. These nanofiber sheets with porous PVB fibers could be a good candidate for high-efficiency filter materials in comparison to smooth fibers without pores.

Highlights

Many literature references discuss the production of porous nanofibers in the electrospinning process
The results show that the vapor pressure of the solvents plays an important role in fiber diameter and porosity
Hansen solubility parameter (HSP) was found as a useful tool for the prediction of suitable solvents for preparation of the porous nanofibers via the electrospinning process

Summary

Introduction

Many literature references discuss the production of porous nanofibers in the electrospinning process. There are a lot of methods, such as the extraction of a component from bicomponent nanofibers, phase separation during electrospinning, and production of porous nanofibers under specific process conditions (temperature, humidity). These methods are technically difficult and demand two step production or special additional device [1,2,3]. In the method’s simplets form, a polymer is dissolved in a two-component solvent mixture consisting of volatile good solvent and an involatile poor solvent for a polymer This two-component polymer solution is cast on a glass plate.

Methods

Results

Conclusion