Institute for Nonlinear Sciences and Applied Mathematics

    第46回 広島大学INSAMセミナー (2002年度)
  題目:Templates, surface patterns and electric field effects
          in copolymer films

  講師:David Andelman 氏 (Tel Aviv University in Israel)


  場所:広島大学理学部  D207

 Block copolymers are polymeric systems exhibiting modulated spatial
structure on the nanometer to micrometer scale. They have many
applications due to their mesoscopic self-assembled structures, which
exhibit combination of several, sometimes complementary, desired physical
and chemical properties.

We consider theoretically several ordering mechanisms in thin films of
diblock copolymers. For temperatures above the order-disorder temperature,
a linear response theory gives the polymer density in the vicinity of
chemically patterned and flat surfaces. The surface pattern or template is
decomposed into its Fourier modes, and the decay of these modes is
analyzed. Below the order-disorder temperature, the transition of parallel
to perpendicular orientation is investigated for homogeneous surface
fields, as well as the stability of tilt lamellar phases for periodic
surface fields. In addition, we investigate the orientation of lamellar
phases in presence of an externally applied perpendicular electric field.
We show that perpendicular ordering is favored above some critical value
of the field. The obtained phase diagram depends on electric field
strength, film thickness and surface interactions. Finally, we report new
results related to the BCC to HEX transition in thin films. We discuss the
importance of both the dielectric effect as well as free (mobile) ions on
the transition.



事務局連絡先:739-8526 東広島市鏡山1丁目 3-1 広島大学

       大学院理学研究科 数理分子生命理学専攻 太田 隆夫
       Tel: 0824-24-7335 ohta@math.sci.hiroshima-u.ac.jp

       大学院先端物質科学研究科 量子物質科学専攻 草野完也
       Tel: 0824-24-7016 kusano@hiroshima-u.ac.jp