Effect of Pluronic Introduction to Polycaprolactone Substrate on the Blend Hydrophilicity by Molecular Dynamic Simulation

Document Type : Research Paper

Authors

Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box: 15875-4413, Tehran, Iran

Abstract

Poly()ε-caprolactone) ()PCL) has been widely investigated for medical applications because of its good physicochemical properties; however hydrophobic nature of PCL has been a colossal obstacle toward achieving scaffolds which offer satisfactory cell attachment and proliferation. To date, different methods have been proposed to lower the hydrophobicity of PCL. Moreover, molecular dynamic simulation (MD) is an excellent method to predict and study the chemical and physical properties of polymeric systems. To this end, MD study was assigned to evaluate the PCL/Pluronic blend. Moreover, some experimental data on PCL/Pluronic blend were collected and compared with the simulated results. Thermodynamic properties of neat and blended PCL were also calculated using MD simulation. The blend of PCL/Pluronic possessed lower density and higher free volume in comparison with neat PCL because of high mobility and low glass transition temperature of Pluronic chains and due to good molecular interactions between polypropylene oxide blocks of Pluronic and PCL. The ratio of the bulk to shear modulus revealed a toughened PCL blended substrate in comparison to its pure form. Moreover, a high interaction energy between the PCL/Pluronic blend and water molecules was observed due to the thermodynamically favored interactions of polyethylene oxide blocks of Pluronic and water molecules. Mean square displacement of water molecules at the bulk and in the surface of water layer placed in the vicinity of neat and blended PCL was calculated. The results revealed a difference between the behavior of the bulk and interfacial water molecules. Water contact angle measurements were carried out in order to evaluate the simulation results and demonstrated a considerable improvement in hydrophilicity of the PCL thin layers when blended with Pluronic.

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