Surface-active fluorocarbon end-functionalized polylactides

The synthesis and surface properties of a 2 × C₈F₁₇ fluorocarbon di-functionalized poly(d,l-lactide), “F2PLA” are described. Small fractions ∼5% w/w of F2PLA, when blended with unfunctionalized poly(d,l-lactide), “PLA”, render the surface both hydrophobic and lipophobic. Contact angle analysis indicates that the properties of the blend surface approach those of PTFE. Rutherford backscattering analysis of the surface shows that at saturation, approximately 50% of the blend surface is covered by C₈F₁₇ fluorocarbon units. Using self-consistent field theory simulations, we estimate that adsorption of the F2PLA is characterized by a thermodynamic sticking energy of the difunctional group of approximately 6 k_BT. Bilayer samples were prepared in which a blend of F2PLA in PLA was initially covered with a layer of pure PLA. The rate of surface modification in these films was analysed to obtain a diffusion coefficient of up to 160 nm² s⁻¹ for 21.6 kg/mol F2PLA at 90 °C.