Modification of Surfaces Using Polymers: A Self-consistent Field Theory Study David Trombly Advised by  Venkat Ganesan The...
Polymer-grafted surface Interacting surface Mediating  material Solvent Melt <ul><ul><li>Biocompatible surfaces </li></ul>...
Polymer-grafted surface Interacting surface Mediating  material Solvent Melt http://www.questline.com/images/content/CMPND...
Polymer-grafted surface Interacting material Homopolymer Surface-polymer interactions Diblock copolymer Random copolymer b...
Polymer-grafted particle Interacting surface Mediating  material Solvent Melt <ul><ul><li>Biocompatible surfaces </li></ul...
Drug design equation <ul><ul><li>Trombly and Ganesan, JPS(B), 2009 </li></ul></ul>
Polymer-grafted particle Interacting surface Mediating  material Solvent Melt The following contribute to miscibility: Dec...
Width/energy collapse, correlation <ul><ul><li>Trombly and Ganesan, JCP, 2010 </li></ul></ul>
Semiconductor devices (Ch 4-5) Equal surface energies  Perpendicular lamellae  High value semiconductor devices Random cop...
Wetting Dewetting σ  = 2.45,  α  = 0.5 σ  = 4.90,  α  = 1.5 <ul><ul><li>Ferriera, et al, Macro, 1998 </li></ul></ul>Happen...
<ul><ul><li>Kim, et al, Macro, 2009 </li></ul></ul>Background: f = 0 <ul><ul><li>Borukhov and Leibler, 2000 </li></ul></ul...
Self-consistent field theory (SCFT) w A ( r ), w B ( r ) q( r ,s) q c ( r ,s) s Stretching energy Enthalpy Incompressibili...
<ul><li>Mimic experiment by using conditional probabilities to create sequences of random chains (f,  λ ) </li></ul>Modeli...
<ul><li>Used to build a modified strong-stretching theory </li></ul>Chain rearrangement <ul><ul><li>Trombly, Pryamitsyn an...
Strong-stretching theory (SST) <ul><ul><li>Kim, et al, Macromolecules, 2009 </li></ul></ul>Configurational entropy cost du...
Surface energy results Autophobic ~ 5 x 10 -3 <ul><ul><li>Trombly, Pryamitsyn and Ganesan, JCP, 2011 </li></ul></ul>χ N = ...
Blockiness and chain rearrangement <ul><ul><li>Trombly, Pryamitsyn and Ganesan, Submitted to JCP, 2011 </li></ul></ul><ul>...
Blockiness and chain rearrangement <ul><ul><li>Trombly, Pryamitsyn and Ganesan, Submitted to JCP, 2011 </li></ul></ul><ul>...
Summary <ul><li>SCFT and SST used to describe random copolymer brush + homopolymer melt </li></ul><ul><li>Chain rearrangem...
Previous modeling work Matsen, JCP, 1997 B A Diblock on hard surface with preference for A Incommensurate Diblock on hard ...
<ul><li>Interpenetration of brush and diblock </li></ul><ul><li>Rearrangement effects </li></ul>Parallel morphologies
<ul><li>Splaying effects – enables the creation of a more neutral surface </li></ul><ul><li>Rearrangement effects (more pr...
<ul><li>Minimal splaying effects </li></ul><ul><li>Very enhanced rearrangement </li></ul>Blocky random copolymer
<ul><li>Enhanced splaying of A diblock </li></ul><ul><li>Assymetric splaying and rearrangement of brush </li></ul>Increase...
<ul><li>Bulk spacing preserved </li></ul><ul><li>“ Super neutrality” due to splaying and rearrangement effects </li></ul>E...
Neutral windows <ul><li>More blocky: larger neutral window due to increased difference in rearrangement between perpendicu...
Neutral windows <ul><li>Neutral windows uncorrelated with surface energies </li></ul><ul><li>No “neutral window” of surfac...
Summary <ul><li>SCFT and SST used to describe random copolymer brush + diblock copolymer melt </li></ul><ul><li>Pictures o...
Future work <ul><li>Modeling grafted water-soluable polymers </li></ul><ul><li>Modeling the effects of air and substrate s...
Acknowledgements  Prof. Venkat Ganesan, Committee members, Ganesan research group (Victor Pryamitsyn, Manas Shah, Landry K...
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  • The reason polymer-particle systems are of interest is that they can be used to study a number of systems. For example… Don’t talk too long about this!
  • The reason polymer-particle systems are of interest is that they can be used to study a number of systems. For example… Don’t talk too long about this!
  • I: Au(2) PS(10)-SH; P = 125, N = 10; sigma = 1.67 II: Au(5) PS(10)-SH; P = 125, N = 10; sigma = 1.39 III: Au(2) PS(10)-SH; P = 125, N = 480; sigma = 9.21 Tell why we model plate + brush
  • Say it right!
  • poly~methyl methacrylate! ~PMMA! and poly~vinyl chloride! ~PVC!, poly~styrene! ~PS!, and poly~2,6-dimethyl-1,4-phenylene oxide! ~PXE! State objectives differently – motivate how we are extending the problem from the limiting cases
  • Mention the presence of two kinds of chains We are proposing that SCFT provides a good way to study these systems
  • I: Au(2) PS(10)-SH; P = 125, N = 10; sigma = 1.67 II: Au(5) PS(10)-SH; P = 125, N = 10; sigma = 1.39 III: Au(2) PS(10)-SH; P = 125, N = 480; sigma = 9.21 Tell why we model plate + brush
  • What really matters is fEff
  • Describe the interplay between enthalpy and entropy using SST Term 4 distinguishes the theory from autophobic Term 4 should be smaller for larger f Random copolymer should rearrange itself toward f = 1 Idea: modify term 4 based on fEff
  • I: Au(2) PS(10)-SH; P = 125, N = 10; sigma = 1.67 II: Au(5) PS(10)-SH; P = 125, N = 10; sigma = 1.39 III: Au(2) PS(10)-SH; P = 125, N = 480; sigma = 9.21 Tell why we model plate + brush
  • I: Au(2) PS(10)-SH; P = 125, N = 10; sigma = 1.67 II: Au(5) PS(10)-SH; P = 125, N = 10; sigma = 1.39 III: Au(2) PS(10)-SH; P = 125, N = 480; sigma = 9.21 Tell why we model plate + brush
  • I: Au(2) PS(10)-SH; P = 125, N = 10; sigma = 1.67 II: Au(5) PS(10)-SH; P = 125, N = 10; sigma = 1.39 III: Au(2) PS(10)-SH; P = 125, N = 480; sigma = 9.21 Tell why we model plate + brush
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Curvature?
  • Defense

    1. 1. Modification of Surfaces Using Polymers: A Self-consistent Field Theory Study David Trombly Advised by Venkat Ganesan Thesis Defense June 29, 2011
    2. 2. Polymer-grafted surface Interacting surface Mediating material Solvent Melt <ul><ul><li>Biocompatible surfaces </li></ul></ul><ul><ul><li>Preventing immune-response induced thrombosis </li></ul></ul>R drug H brush R protein σ Surface-surface interactions <ul><ul><li>Water purification </li></ul></ul><ul><ul><li>Targeted drug delivery </li></ul></ul>
    3. 3. Polymer-grafted surface Interacting surface Mediating material Solvent Melt http://www.questline.com/images/content/CMPND_nanocomposites.jpg Surface-surface interactions <ul><ul><li>Polymer thin films/electronic materials </li></ul></ul>Surface-polymer interactions
    4. 4. Polymer-grafted surface Interacting material Homopolymer Surface-polymer interactions Diblock copolymer Random copolymer brush Stoykovich, et al., Science, 2005 B A
    5. 5. Polymer-grafted particle Interacting surface Mediating material Solvent Melt <ul><ul><li>Biocompatible surfaces </li></ul></ul><ul><ul><li>Custom particles </li></ul></ul><ul><ul><li>Preventing immune-response induced thrombosis* </li></ul></ul>R drug H brush R protein σ R g 2 Interaction energy determined by: σ www.mdconsult.com Polymer-grafted sphere – bare sphere (Ch 2) R protein R drug H brush R drug
    6. 6. Drug design equation <ul><ul><li>Trombly and Ganesan, JPS(B), 2009 </li></ul></ul>
    7. 7. Polymer-grafted particle Interacting surface Mediating material Solvent Melt The following contribute to miscibility: Decrease: Increase: N brush N free translational entropy σ R g 2 <ul><ul><li>Meli, et al, Soft Matter, 2009 </li></ul></ul>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. 8. Width/energy collapse, correlation <ul><ul><li>Trombly and Ganesan, JCP, 2010 </li></ul></ul>
    9. 9. Semiconductor devices (Ch 4-5) Equal surface energies Perpendicular lamellae High value semiconductor devices Random copolymer brush f A B f = volume fraction of A (in brush) B A <ul><ul><li>Mansky et al, Science, 1997 </li></ul></ul><ul><li>Model a homopolymer thin film on top of a random copolymer brush </li></ul><ul><li>Study the effect of f, segment-segment interaction, chain lengths, grafting density on surface energy </li></ul>Objectives (Ch 4)
    10. 10. Wetting Dewetting σ = 2.45, α = 0.5 σ = 4.90, α = 1.5 <ul><ul><li>Ferriera, et al, Macro, 1998 </li></ul></ul>Happens sooner for larger σ (more stretched chains)! Surface energy <ul><ul><li>Matsen and Gardiner, JCP, 2001 </li></ul></ul>Background: f = 1 (autophobic) Increased free chain length ( α ) α = Same effect from decrease of brush chain length (increases α ) Ends of free chains are stretched at interface; reduction of interfacial area is preferred N free N brush
    11. 11. <ul><ul><li>Kim, et al, Macro, 2009 </li></ul></ul>Background: f = 0 <ul><ul><li>Borukhov and Leibler, 2000 </li></ul></ul>Objectives <ul><li>Model a homopolymer thin film on top of a random copolymer brush </li></ul><ul><li>Surface energies as a function of f, χ N, α , σ , λ </li></ul>
    12. 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. 13. <ul><li>Mimic experiment by using conditional probabilities to create sequences of random chains (f, λ ) </li></ul>Modeling random copolymers <ul><li>How do we model the random chains? </li></ul><ul><li>Solve the equations, average the results </li></ul><ul><li>n = 500, average the results of two independent runs </li></ul><ul><ul><li>Fredrickson, et al, Macromolecules, 1992 </li></ul></ul>λ = -0.5 λ = 0.5 λ = 0
    14. 14. <ul><li>Used to build a modified strong-stretching theory </li></ul>Chain rearrangement <ul><ul><li>Trombly, Pryamitsyn and Ganesan, JCP, 2011 </li></ul></ul>f Eff f Eff f = 0. 5 f = 0. 5
    15. 15. Strong-stretching theory (SST) <ul><ul><li>Kim, et al, Macromolecules, 2009 </li></ul></ul>Configurational entropy cost due to the interface Translational entropy Enthalpic interactions <ul><ul><li>Matsen and Gardiner, JCP, 2001 </li></ul></ul><ul><ul><li>Semenov, Macro, 1993 </li></ul></ul>Stretching energy χ Eff = χ (1-f Eff )
    16. 16. Surface energy results Autophobic ~ 5 x 10 -3 <ul><ul><li>Trombly, Pryamitsyn and Ganesan, JCP, 2011 </li></ul></ul>χ N = 10, α = 1, σ = 4.9, λ = 0 f = 0.5, α = 1, σ = 4.9, λ = 0 f = 0.5, χ N = 10, σ = 4.9, λ = 0 f = 0.5, χ N = 10, α = 1, λ = 0 <ul><li>Autophobic trends </li></ul>
    17. 17. Blockiness and chain rearrangement <ul><ul><li>Trombly, Pryamitsyn and Ganesan, Submitted to JCP, 2011 </li></ul></ul><ul><li>Rearrangement of the grafted chains </li></ul>f = 0.5 f = 0.5
    18. 18. Blockiness and chain rearrangement <ul><ul><li>Trombly, Pryamitsyn and Ganesan, Submitted to JCP, 2011 </li></ul></ul><ul><li>Rearrangement of the grafted chains </li></ul>f = 0.5 f = 0.5
    19. 19. Summary <ul><li>SCFT and SST used to describe random copolymer brush + homopolymer melt </li></ul><ul><li>Chain rearrangement </li></ul><ul><li>Surface energies as a function of f, χ N, α , σ , λ </li></ul>Extension (Ch 5) <ul><li>Model a diblock coploymer thin film on a random copolymer brush </li></ul>
    20. 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. 21. <ul><li>Interpenetration of brush and diblock </li></ul><ul><li>Rearrangement effects </li></ul>Parallel morphologies
    22. 22. <ul><li>Splaying effects – enables the creation of a more neutral surface </li></ul><ul><li>Rearrangement effects (more pronounced the parallel) </li></ul>Perpendicular morphologies
    23. 23. <ul><li>Minimal splaying effects </li></ul><ul><li>Very enhanced rearrangement </li></ul>Blocky random copolymer
    24. 24. <ul><li>Enhanced splaying of A diblock </li></ul><ul><li>Assymetric splaying and rearrangement of brush </li></ul>Increased A in brush (f = 0.6)
    25. 25. <ul><li>Bulk spacing preserved </li></ul><ul><li>“ Super neutrality” due to splaying and rearrangement effects </li></ul>Energy picture D bulk <ul><li>Transition to parallel morphologies with increasing f </li></ul>
    26. 26. Neutral windows <ul><li>More blocky: larger neutral window due to increased difference in rearrangement between perpendicular and parallel </li></ul><ul><li>“ Super neutrality” due to splaying and rearrangement effects </li></ul>
    27. 27. Neutral windows <ul><li>Neutral windows uncorrelated with surface energies </li></ul><ul><li>No “neutral window” of surface energies can be drawn. </li></ul>
    28. 28. Summary <ul><li>SCFT and SST used to describe random copolymer brush + diblock copolymer melt </li></ul><ul><li>Pictures of morphology, chain rearrangement </li></ul><ul><li>Neutral as a function of f, α , σ , λ </li></ul>
    29. 29. Future work <ul><li>Modeling grafted water-soluable polymers </li></ul><ul><li>Modeling the effects of air and substrate surface interactions on the phase behavior of diblock copolymer thin films </li></ul><ul><li>Exploring the phase behavior of random-block copolymers </li></ul><ul><li>Exploring the phase behavior of thin films of assymetric diblock copolymers on random copolymer brushes </li></ul>
    30. 30. Acknowledgements Prof. 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
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