Synthesis and Surface Properties of Fluorocarbon End-Capped Biodegradable Polyesters

Abstract

We report the synthesis and characterization of a new class of materials based on combining hydrolytically degradable polyesters and fluorocarbon surface chemistry. These materials have surface properties which overcome some of the limitations of polymeric materials in controlled cellular or tissue adhesion properties. Fluorocarbon chains of two lengths (CF 3(CF2)m(CH2)n, where F7C1 and F10C2 represent m ) 6 and n ) 1 and m ) 9 and n ) 2, respectively) have been synthesized as the terminal end groups to L-and DL-polylactides (PLA) and poly(lactide-co-glycolide) copolymers. Using both ring-opening polymerization and the substitution of the fluorocarbon at terminal hydroxyl groups, polyesters with 1, 2, and 4 fluorocarbon end groups were obtained (F-polyesters). Angular dependent X-ray photoelectron spectroscopy (XPS or ESCA) revealed that end groups are segregated at the surface. Further, the results show their the surface coverage of fluorocarbon groups increases with increasing the concentration and the length of fluorocarbon end groups. The surface composition of F-polyesters can be controlled by blending these polymers with polyesters or by changing the architecture of fluorocarbon end groups. From ESCA data of F-polyesters after in-vitro hydrolysis at pH ) 11.4, results from the F-polyester with a longer fluorocarbon end group (F10C2-) show that the surface erosion occurs at the topmost surface region during the initial hydrolysis period. The F-polyester having a short fluorocarbon group (F7C1-) shows a progressive decrease of surface fluorocarbon concentration as a function of hydrolysis time. This result is explained by a longer retardation time for water permeation into the sample bulk of F10C2-L-PLA due to greater segregation of fluorocarbon groups at the topmost surface.

Fluorocarbon End‐functionalized Polymers from Poly(arylether) Dendritic Initiators

“…Experiments were carried out using an NEC 5SDH pelletron ion beam accelerator. A beam of 3 He þ ions was accelerated to 0.7 MeV and directed onto the sample surface at 838 to the sample normal (''grazing incidence''). Backscattered protons arising from the d(3He,p)a nuclear reaction [12] were detected at 1708 to the incident beam.…”

“…[1][2][3] It is well-known that perfluoroalkyl groups are attracted to an exposed surface of materials due to their low surface energy. [3][4][5] A practical limitation of the use of fluorocarbon groups to modify hydrocarbon polymers is their poor solubility in most organic solvents.…”

Ultra-high-speed fluorescence imaging

“…Here, an oil-in-water emulsion was used, in which the oil phase consisted of a mixture of the shell-forming polymer, in this case perfluoroctanolpoly(lactic acid) (PFO-PLLA) [126], a volatile solvent, dichloromethane, and a non-volatile non-solvent, decane. As the dichloromethane started to evaporate small polymerrich droplets were formed by phase separation within the emulsion droplets.…”

“…Poly(l-lactic acid) terminated by PFO was synthesized according to Lee et al [126]. PFO (1.02 g, 2.55 mmol) and l-lactide (6.61 g, 0.46 mol) were suspended in toluene (50 mL) under an argon atmosphere, while stirring.…”

“…These bubbles often indent through a buckling instability, which is a way to conserve their surface area and allow for a change in the volume. By using fluorinated polymers for the microbubble shell, the water intrusion through pores in the shell is very much reduced due to the hydrophobic surface properties of these polymers [23,41,126].…”