Electrospun Nanofiber Orientation

Written by: Francisco Chaparro

Fiber orientation is crucial for different applications and can be controlled during fiber production. Typical orientations obtained during solution electrospinning processing are randomly and aligned fibers. While some applications like water filtration require randomly oriented fibers to maximize pollutant sequestration, other applications like specialized tissue engineer require aligned fibers to improve cell proliferation and regeneration. Below, two SEM pictures taken with our Phenom XL system, show the difference of polyacrylonitrile fiber alignment when low (left) and high (right) linear speeds are used in the Fluidnatek LE-100.

Polyacrylonitrile electrospun fibers
Aligned (left) vs random (right) polyacrylonitrile electrospun fibers achieved at low and high linear speeds, respectively.

Fiber orientation has a big impact on mechanical properties and will affect the behavior of the mechanical test being done. For example, aligned fibers will have minimal force when suture retention strength (a mechanical test typically done for blood vessel assessment) is used, but a higher force when a stress-strain tensile test is implemented. For this reason, all Fluidnatek systems are engineered to be used up to 2,000 rpm’s, achieving linear speeds up to 1,256 m min-1. The image below shows our Fluidnatek LE-500 system with a rotating drum ready to collect random and aligned fibers, according to the RPM’s used.

Single Coaxial Emitter on the Fluidnatek LE-500
Fluidnatek LE-500 showing the use of a single co-axial emitter and a rotating drum to collect random or aligned electrospun fibers.