J. Ruokolainen, R. Mäkinen, M. Torkkeli, T. Mäkelä, R. Serimaa, G. ten Brinke, ^* O. Ikkala ^*

It was demonstrated that polymeric supramolecular nanostructures with several length scales allow straightforward tailoring of hierarchical order-disorder and order-order transitions and the concurrent switching of functional properties. Poly(4-vinyl pyridine) (P4VP) was stoichiometrically protonated with methane sulfonic acid (MSA) to form P4VP(MSA)_1.0, which was then hydrogen-bonded to pentadecylphenol. Microphase separation, re-entrant closed-loop macrophase separation, and high-temperature macrophase separation were observed. When MSA and pentadecylphenol were complexed to the P4VP block of a microphase-separated diblock copolymer poly[styrene-block-(4-vinyl pyridine)], self-organized structures-in-structures were obtained whose hierarchical phase transitions can be controlled systematically. This microstructural control on two different length scales (in the present case, at 48 and 350 angstroms) was then used to introduce temperature-dependent transitions in electrical conductivity.

J. Ruokolainen and O. Ikkala, Department of Engineering Physics and Mathematics, Helsinki University of Technology, FIN-02015 HUT, Espoo, Finland.
R. Mäkinen, M. Torkkeli, R. Serimaa, Department of Physics, University of Helsinki, Post Office Box 9, FIN-00014, Helsinki, Finland.
T. Mäkelä, VTT Microelectronics, Technical Research Centre of Finland, Post Office Box 1101, FIN-02044 VTT, Espoo, Finland.
G. ten Brinke, Department of Polymer Science and Materials Science Center, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands.
^*   To whom correspondence should be addressed. E-mail: G.ten.Brinke{at}chem.rug.nl; Olli.Ikkala{at}hut.fi