Understanding the role of dip-coating process parameters in the mechanical performance of polymer-coated bioglass robocast scaffolds

摘要

The effect of different dip-coating variables solvent, deposition temperature and polymer concentration on the mechanical performance of polycaprolactone-coated 4555 bioglass robocast scaffolds is systematically analyzed in this work. The reproducible geometry of the scaffolds produced by this additive manufacturing technique makes them an optimal model system and facilitates the analysis. The results suggest that the mechanical performance of the hybrid scaffolds is improved monotonically with polymer concentration, but this concentration cannot be increased indefinitely if the macroporosity inter connectivity, and thus the scaffold's capacity to promote tissue ingrowth, are to be preserved. An optimal concentration, and therefore viscosity (similar to 1-4 Pa s in the present case), exists for any given set of process variables (scaffold geometry and material, polymer, solvent and process temperature) that yields coatings with optimal reinforcement and minimal reduction of scaffold functionality. Solvent and process temperature do not directly affect the strengthening provided by the polymeric coating. However they can determine the maximum concentration at the critical viscosity, and thereby the maximum achievable mechanical performance of the resulting hybrid scaffold. (C) 2016 Elsevier Ltd. All rights reserved.