Globular/semiglobular Poly(ethylene glycol) nanostructures enveloped between polythiophenes with/without side chains via Y-Shaped copolymers

Abstract

Y-type block copolymers were synthesized based on the poly(ethylene glycol) (PEG), polythiophene (PTh), and poly(3-dodecyl thiophene) (PDDTh) precursors including PEG-b-(PTh)2 and PEG-b-(PDDTh)2. Polymers were applied in designing the semiglobular (semiglob(PEG-star-PTh)) and globular (glob(PEG-star-PDDTh)) nanostructures, in which the PEG lamellar crystals were confined between the PTh and PDDTh chains without and with alkyl side chains, respectively. The designed scrolled configurations were comprehensively investigated from the perspectives of curvature, crystal dimension, side chain effect, etc. Thanks to a low enough crystallization temperature (Tc = 10 °C), the PEG blocks were capable of being assembled into the ordered lamellar structures, which was verified by the selected area electron diffraction (SAED) patterns. According to (120) growth prisms in grazing incidence wide-angle X-ray scattering (GIWAXS), the average d-spacing values of 4.70 and 4.75 Å were acquired for the sandwiched PEG crystals between PTh and PDDTh chains, respectively, demonstrating the higher ordering in alkyl side chain-less systems. The molecular weights of PDDTh and PTh arms were to some extent the same and this was the role of alkyl side chains in PDDTh chains which provided a higher surface stress on the PEG arrangements. The narrower PEG crystals (16–22 nm versus 45–50 nm) as well as a higher degree of curvature were reached in the glob(PEG-star-PDDTh) nanostructures.