IntroductionElectrospinning is a widely-known fabrication technique for nanofires. With the emerging of novel, nano-structured polymers, this process needs to be re-evaluated and modified to produce replicable, consistent... [ view full abstract ]
Introduction
Electrospinning is a widely-known fabrication technique for nanofires. With the emerging of novel, nano-structured polymers, this process needs to be re-evaluated and modified to produce replicable, consistent results for each type of materials.
This project focuses on the production and characterisation of nano-fibrous scaffold from a novel, biodegradable polyurethane-based nanocomposite using electrospinning. To create a stable jet stream and generate reproducible fibers, the solution formulation, environmental factors such as temperature and humidity and solution factors such as solvent and polymer-composition were investigated.
Methods
POSS-terminated aliphatic polyester-urethane-urea (PEUU-POSS) solution was produced in-house at a concentration of 18%(DMAc). A custom made electospinning set up, allowing us to monitor and control humidity and temperature, was used.
Random fibers were generated at a distance of 35cm, a voltage of 13kV and a flow rate of 1ml/h. To characterise the produced scaffolds a degradation profile was determined by immersing the scaffolds in PBS. Mechanical properties, changes in surface wettability(contact angle) after electrospinning were also evaluated.
Results
The recorded humidity ranged from 35% to 51%, Temperatures ranged from 20C to 30C. Fibres were obtained at a distance of 35cm, a voltage of 13kV and a flow rate of 1ml/h if humidity was under 39%, between 39% and 49% individual particles were created, above 50% wet patches with no morphology appeared. Temperatures above 25C at all humidities created stable fibres, while at lower temperatures fibre formation was dependent on the surrounding temperature.
The stable, native scaffolds(Figure 1) showed a fibre-diameter in a range of 500 nm to 1.1±0.36 mm, a Young’s Modulus of 6±1.6 kPa and super high ultimate strain 575%. Contact angle measurement for random scaffolds returned hydrophobic readings of 119.4±8.28°, which decreased over the course of a 5-week degradation study. Weight decreased by nearly 50% during the first two weeks and then plateaued. UV spectrum analysis showed an increase of break down products of polymer.
Discussion
PEUU-POSS is a promising novel biodegradable polymer with remarkable hyperplastic-mechanical properties. Further work is required into its processing, which is currently limited by the selection of solvents.
Polymer nanocomposites , Tissue engineering and regenerative nanomedicine , Nanofabrication, nanoprocesing & nanomanufacturing
