Branched Block Copolymers for Tuning of Morphology and Feature Size in Thin Film Nanolithography

Minehara, H., Pitet, L. M., Kim, S., Zha, R. H., Meijer, E. W., Hawker, C. J.
49 (6), pp 2318–2326

A library of Y-shaped poly(dimethylsiloxane) (PDMS)-b-poly(d,l-lactide) (PLA) diblock copolymers and their corresponding linear counterparts were synthesized, and their morphologies and feature sizes in bulk and thin films were compared using small-angle X-ray scattering (SAXS), scanning force microscopy (SFM), and grazing incidence small-angle X-ray scattering (GI-SAXS). For macromolecular isomers with approximately the same molecular weights and volume fractions (PLA fL: 0.20 and 0.35), different thin film morphologies were obtained for the Y-shaped PDMS-b-PLA derivatives when compared to the corresponding linear derivatives. These data also gave us the option to determine some of the key parameters of these block copolymers. A relatively high χ value of 0.24 was found for these PDMS-b-PLA systems and was shown to be influenced by architecture.