Synthesis, characterization, and morphology studies of biodegradable amphiphilic poly[(R)-3-hydroxybutyrate]-alt-poly(ethylene glycol) multiblock copolymers.
Novel biodegradable amphiphilic alternating block copolymers based on poly[(R)-3-hydroxybutyrate] (PHB) as biodegradable and hydrophobic block and poly(ethylene glycol) (PEG) as hydrophilic block (PHB-alt-PEG) were successfully synthesized through coupling reaction. Their chemical structures have been characterized by using gel permeation chromatography, (1)H nuclear magnetic resonance, and Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) analysis revealed that both PHB and PEG blocks in PHB-alt-PEG block copolymers can crystallize to form separate crystalline phase except in those with a short PEG block (M(n) 600) only PHB crystalline phase has been observed. However, due to the mutual interference from each other, the melting transition of both PHB and PEG crystalline phases shifted to lower temperature with lower crystallinity in comparison with corresponding pure PHB and PEG. The crystallization behavior of PHB block and PEG block has also been studied by X-ray diffraction, and the results were in good agreement with those deduced from DSC study. The surface morphologies of PHB-alt-PEG block copolymer thin films spin-coated on mica have been visualized by atomic force microscopy with tapping mode, indicating formation of laterally regular lamellar surface patterns. Static water contact angle measurement revealed that surface hydrophilicity of these spin-coated thin films increases with increasing PEG block content.
Li
Xu
X
Institute of Materials Research and Engineering, National University of Singapore, 3 Research Link, Singapore.
Liu
Kerh Li
KL
Li
Jun
J
Tan
Eunice Phay Shing
EP
Chan
Lee Meng
LM
Lim
Chwee Teck
CT
Goh
Suat Hong
SH
D002850:Chromatography, Gel; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D000094122:Polyhydroxybutyrates
D011091:Polyesters; D011092:Polyethylene Glycols; D011108:Polymers; C515859:poly(3-hydroxybutyrate)-alt-poly(ethylene glycol) multiblock copolymer; D000094122:Polyhydroxybutyrates