Halogen-bonded mesogens direct polymer self-assemblies up to millimetre length scale
Nikolay Houbenov1, Roberto Milani2, Mikko Poutanen1, Johannes Haataja1, Valentina Dichiarante3, Jani Sainio1, Janne Ruokolainen1, Giuseppe Resnati3, Pierangelo Metrangolo2,3 & Olli Ikkala1
1 Department of Applied Physics, Aalto University (formerly Helsinki University of Technology), PO Box 15100, FI-02150 Espoo, Finland.
2 Process Chemistry and Environmental Engineering, VTT Technical Research Centre of Finland, PO Box 1000, FI-02044 VTT, Finland.
3 Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials and Chemical Engineering ‘‘Giulio Natta’’, Politecnico di Milano, Via Mancinelli 7, I-20131 Milano, Italy.
Nature Communications 5, Article number: 4043 doi:10.1038/ncomms5043
Received 03 February 2014; Accepted 04 May 2014; Published 04 June 2014
Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in materials science and technology. Here we show polymeric self-assemblies where nanoscale organization guides the macroscopic alignment up to millimetre scale. The concept is shown by halogen bonding mesogenic 1-iodoperfluoroalkanes to a star-shaped ethyleneglycol-based polymer, having chloride end-groups. The mesogens segregate and stack parallel into aligned domains. This leads to layers at B10nm periodicity. Combination of directionality of halogen bonding, mesogen parallel stacking and minimization of interfacial curvature translates into an overall alignment in bulk and films up to millimetre scale. Upon heating, novel supra-molecular halogen-bonded polymeric liquid crystallinity is also shown. As many polymers present sites capable of receiving halogen bonding, we suggest generic potential of this strategy for aligning polymer self-assemblies.
