Electrospinning of cellulose and SWNT-cellulose nano fibers for smart applications

Recently, electrospinning has attracted a great deal of attention as a means of producing non-woven membranes of nanofibers due to its simple methodology and the promise of nano applications. Despite its simplicity and relative low cost, there still remain a number of challenges associated with this process, such as low fiber production, presence of beads and repeatability issues due to the large number of experimental variables. In this paper, we investigated the use of the Design of Experiments (DOE) method and factorial testing as a means to identify the optimum electrospinning conditions and ensure repeatability of the process. We focused on two polymer solutions as the model systems, namely pure cellulose and cellulose with single wall carbon nanotubes (SWNTs). During the electrospinning experiment, we carefully monitored and adjusted the environmental conditions due to the highly sensitive nature of the solutions. We also adopted various ways of reducing surface tension to promote electrospinning, including convective heating of the solutions. As a first step, through initial screening using the DOE method, we eliminated the experimental variables that were less crucial to the electrospinning process, namely the distance from the needle to the grounded target and the needle size. Next, we demonstrated that three of the variables, i.e., flow rate, applied voltage and temperature, were essential to initiating the electrospinning process and were responsible for controlling the fiber diameter, dimension consistency, and abundance.