Degradable Polycaprolactone and Polylactide Homopolymer and Block Copolymer Brushes Prepared by Surface-Initiated Polymerization with Triazabicyclodecene and Zirconium Catalysts

• Published in: Langmuir 2015-09, Vol.31 (37), p.10183-10189
• Main Authors: Grubbs, Joe B, Arnold, Rachelle M, Roy, Anandi, Brooks, Karson, Bilbrey, Jenna A, Gao, Jing, Locklin, Jason
• Format: Article
• Language: English
• Subjects: Azabicyclo Compounds - chemistry; Catalysis; Polyesters - chemistry; Polymerization; Polymers - chemistry; Zirconium - chemistry
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.5b02093

Surface-initiated ring-opening polymerization (SI-ROP) of polycaprolactone (PCL) and polylactide (PLA) polymer brushes with controlled degradation rates were prepared on oxide substrates. PCL brushes were polymerized from hydroxyl-terminated monolayers utilizing triazabicyclodecene (TBD) as the polymerization catalyst. A consistent brush thickness of 40 nm could be achieved with a reproducible unique crystalline morphology. The organocatalyzed PCL brushes were chain extended using lactide in the presence of zirconium n-butoxide to successfully grow PCL/PLA block copolymer (PCL-b-PLA) brushes with a final thickness of 55 nm. The degradation properties of “grafted from” PCL brush and the PCL-b-PLA brush were compared to “grafted to” PCL brushes, and we observed that the brush density plays a major role in degradation kinetics. Solutions of methanol/water at pH 14 were used to better solvate the brushes and increase the kinetics of degradation. This framework enables a control of degradation that allows for the precise removal of these coatings.