Template-free fabrication of non-spherical polymeric nanoparticles is desirable for various applications, but has had limited success owing to thermodynamic favorability of sphere formation. Herein we present a simple way to prepare cubic nanoparticles of block copolymers by self-assembly from aqueous solutions at room temperature. Nanocubes with edges of 40–200 nm are formed spontaneously on different surfaces upon water evaporation from micellar solutions of triblock copolymers containing a central poly(ethylene oxide) block and terminal trimethylene carbonate/dithiolane blocks. These polymers self-assemble into 28±5 nm micelles in water. Upon drying, micelle aggregation and a kinetically controlled crystallization of central blocks evidently induce solid cubic particle formation. An approach for preserving the structures of these cubes in water by thiol- or photo-induced crosslinking was developed. The ability to solubilize a model hydrophobic drug, curcumin, was also explored.
Bibliographical noteFunding Information:
This material is based upon work supported by the National Science Foundation under Grant No. (DMR-1407658, RMW). K.M. is thankful to the Stanford Center of Molecular Analysis and Design for supporting her fellowship. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Part of this work was performed at the Stanford Nano Shared Facilities (SNSF), supported by the National Science Foundation under award ECCS-1542152. We thank Ann F. Marshall for her help with TEM experiments and insightful suggestions.
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
- dithiolane crosslinking
- micelle aggregation
- triblock copolymers