Block Copolymers (BCPs) in thin filmsPhenomena: Block copolymer (BCPs) in thin

films with

long range lateral order,

self-assembly

and so on….

Block Copolymers (BCPs) in thin filmsPhysics: We consider aspects of

segmental interactions,

interfacial interactions,

Block Copolymers (BCPs) in thin filmsPhysics: We consider aspects of surface

energy Entropy ..…

1.Morphologies of Block Copolymers

Mean Field theory!!!

Frank S.Bates, Annu.Rev.Phys.Chem.1990.41.525-57

1.Morphologies of Block Copolymers1.1 Effect of confinement: Symmetric/asymmetric wetting

P.F.Green, R.Limary,Advances in Clloid and Interface Science 94,53 (2001)

• Surface induced ordering

1.Morphologies of Block Copolymers1.2 Surface Energy A—higher interfacial energy with the interface as it increases its fraction; B---lower interfacial energy with interface as it decrease its fraction. Commensurability----On one hand, the total energy is lowest; on the other, the amount of each component is fixed. Together they determine the copolymer structures.

E.Huang,S.Pruzinsky,T.P.Russell,J.Mays,C.J.Hawker,Macromolecules 32,5299(1999)

1.Morphologies of Block Copolymers1.3 Heterogeneous Surfaces The strength and lateral distribution of interfacial interactions can direct the BCP morphologies in thin films.

J.Heier, et.al. Macromolecules, 30, 6610 (1997)

•Perfect candidates as templates and scaffolds for the fabrication of nanostructured materials.

•Top down approaches are coupled with a bottom up approach, to obtain multi length scales

control over the ordering and spatial location of nanoscopic elements for device fabrication.

2.Nanopatterning from BCP Thin Films

2.1 zone casting

2.Nanopatterning from BCP Thin Films

A.Tracz, et. al. Journal of the American Chemical Society 125, 1682 (2003)

2.2 Solvent AnnealingThe preparation of BCP thin films under various solvent evaporation

conditions is an effective way to manipulate the orientation and lateral ordering of BCP microdomains in thin films.

2.Nanopatterning from BCP Thin Films

S.H.Kim, et.al. Advanced Materials 16, 226 (2004)

2.3 Optical Alignment Directionally selective light excitation, using linearly polarized light of photoisomerizable molecules in a

liquid-crystalline polymer produced patterned, oriented microdomains in the films.

2.Nanopatterning from BCP Thin Films

K.Ichimura, Chemical Reviews 100, 1847 (2000)

2.4 ShearingBCPs in bulk can easily be aligned by

mechanical shear.

2.Nanopatterning from BCP Thin Films

D.E.Angelescu, et.al. Advanced Materials 16, 1736 (2004)

3.Applications of Nanopatterned BCP Thin Films3.1 Nanoporous Membrane for Filtration of Viruses

S.Y.Yang, et. al. Advanced Materials 18, 709 (2006)

Narrow distribution!High flux!

3.Applications of Nanopatterned BCP Thin Films3.2 Incorporation of Nanocrystals and Nanoreactors Nice little

workshop for nanoparticles.

3.Applications of Nanopatterned BCP Thin Films3.3 Planar Optical Waveguides

D.H.Kim, et. al. Advanced Materials 17,2442 (2005)

A. Schematic diagram of the OWS setup based on the Kretschmann configuration, and of the idealized field distribution of several guided modes in the waveguiding layer.B. Schematic diagram of a thin film of PS-b-PMMA/PMMA homopolymer mixture with PMMA microdomains aligned normal to the substrate.

3.Applications of Nanopatterned BCP Thin Films3.4 Templated Growth of Nanowires

T.Thurn-Albrecht, et. al. Science 290, 2126 (2000)

A. An asymmetric diblock copolymer annealed above the glass transition temperature of the copolymer between two electrodes under an applied electric field, forming a hexagonal array of cylinders oriented normal to the film surface.B. After removal of the minor component, a nanoporous film is formed.C. By electrodepostion, nanowires can be grown in the porous template, forming an array of nanowires in a polymer matrix.