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2. Polymer-grafted surface Interacting surface Mediatingmaterial Solvent Melt
R drug H brush R protein Surface-surface interactions
3. Polymer-grafted surface Interacting surface Mediatingmaterial Solvent Melt http://www.questline.com/images/content/CMPND_nanocomposites.jpg Surface-surface interactions
Surface-polymer interactions 4. Polymer-grafted surface Interacting material Homopolymer Surface-polymer interactions Diblock copolymer Random copolymer brush Stoykovich, et al., Science, 2005 B A 5. Polymer-grafted particle Interacting surface Mediatingmaterial Solvent Melt
R drug H brush R protein R g 2 Interaction energy determined by: www.mdconsult.com Polymer-grafted sphere bare sphere (Ch 2) R protein R drug H brush R drug 6. Drug design equation
7. Polymer-grafted particle Interacting surface Mediatingmaterial Solvent Melt The following contribute to miscibility: Decrease: Increase: N brush N free translational entropy R g 2
Polymer-grafted spheres in a melt (Ch 3) R core H brush R particle N free N brush H brush R core R particle R g, free 8. Width/energy collapse, correlation
9. Semiconductor devices (Ch 4-5) Equal surface energiesPerpendicular lamellaeHigh value semiconductor devices Random copolymer brush f A B f = volume fraction of A (in brush) B A
Objectives (Ch 4) 10. Wetting Dewetting = 2.45,= 0.5 = 4.90,= 1.5
Happens sooner for larger(more stretched chains)! Surface energy
Background: f = 1 (autophobic) Increased free chain length ( ) = Same effect from decrease of brush chain length (increases ) Ends of free chains are stretched at interface; reduction of interfacial area is preferred N free N brush 11.
Background: f = 0
Objectives
12. Self-consistent field theory (SCFT) w A ( r ), w B ( r ) q( r ,s) q c ( r ,s) s Stretching energy Enthalpy Incompressibility Grafted Free 13.
Modeling random copolymers
= -0.5 = 0.5 = 0 14.
Chain rearrangement
f Eff f Eff f = 0. 5 f = 0. 5 15. Strong-stretching theory (SST)
Configurational entropy cost due to the interface Translational entropy Enthalpic interactions
Stretching energy Eff= (1-f Eff ) 16. Surface energy results Autophobic ~ 5 x 10 -3
N = 10,= 1,= 4.9,= 0 f = 0.5,= 1,= 4.9,= 0 f = 0.5, N = 10,= 4.9,= 0 f = 0.5, N = 10,= 1,= 0
17. Blockiness and chain rearrangement
f = 0.5 f = 0.5 18. Blockiness and chain rearrangement
f = 0.5 f = 0.5 19. Summary
Extension (Ch 5)
20. Previous modeling work Matsen, JCP, 1997 B A Diblock on hard surface with preference for A Incommensurate Diblock on hard surface with chemical stripes Wang, et al, Macro, 2000 Commensurate D bulk B A 21.
Parallel morphologies 22.
Perpendicular morphologies 23.
Blocky random copolymer 24.
Increased A in brush (f = 0.6) 25.
Energy picture D bulk
26. Neutral windows
27. Neutral windows
28. Summary
29. Future work
30. AcknowledgementsProf. Venkat Ganesan, Committee members, Ganesan research group (Victor Pryamitsyn, Manas Shah, Landry Khounlavong, Paresh Chokshi, Ben Hanson, Arun Narayana, Chetan Mahajan, Thomas Lewis, Gunja Pandav), Brandon Rawlings Funding: NSF (Award # 1005739) Robert A. Welch Foundation Grant F1599 US Army Research Office Grant W911NF-10-1-0346 Texas Advanced Computing Center