1 / 19

Hole Dynamics in Polymer Langmuir Films

Hole Dynamics in Polymer Langmuir Films. Lu Zou + , James C. Alexander * , Andrew J. Bernoff & , J. Adin Mann, Jr. # , Elizabeth K. Mann +. + Department of Physics, Kent State University * Department of Mathematics, Case Western Reserve University

xenon
Download Presentation

Hole Dynamics in Polymer Langmuir Films

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Hole Dynamics in Polymer Langmuir Films Lu Zou+, James C. Alexander*, Andrew J. Bernoff&, J. Adin Mann, Jr.#, Elizabeth K. Mann+ + Department of Physics, Kent State University * Department of Mathematics, Case Western Reserve University & Department of Mathematics, Harvey Mudd College # Department of Chemical Engineering, Case Western Reserve University Partially under NSF Grant No. 9984304

  2. Why hole-closing is interesting? • Phase coexistence • Biological systems, e.g. cell membrane Cell fluid Protein

  3. A gas-phase hole in a 2D polymer liquid

  4. Fundamental Dynamics Equations • Stokes Equation • Continuity Equation

  5. Assumptions on the surface • 2D liquid phase + very dilute 2D gas • Negligible surface viscosity • Liquid phase: • High elasticity • Incompressible • Gas phase: • Null compressibility • Elasticity = 0 • Circular hole

  6. Assumptions on the subfluid • Incompressible • Bulk viscosity η’ • Flow velocity

  7. Derivation Result –closing rate

  8. Derivation Result –Vertical Motion Vertical Cross section of flow lines in the subfluid

  9. Experimental setup Brewster Angle Microscope Langmuir Trough PDMS = Poly(dimethylsiloxane) Mw=31600 N=427

  10. Hole-closing images • Monolayer thickness ~ 0.7 nm • Surface vibration • Hole Moving around • Surface concentration 0.35 mg/m2 • Monolayer coverage ~ 70% • Monolayer  dark • gaseous hole  bright 0.27mm X 0.44mm

  11. Experimental result [Ref] [Ref]: E. K. Mann, et al., Phys. Rev. E 51, 5708 (1995)

  12. Conclusion • Develop a model for the closing of a gaseous hole in a liquid domain within a 2D fluid layer, coupled to a fluid bulk substrate • Experimental result supports the prediction on the hole-closing rate • Suggest an independent means of determining the line tension • Predict the vertical motion of the underlying incompressible fluid

  13. Future work • Improvement on the current experiment • How to make a better hole? • How to obtain better images? • Observation on the vertical motion of the subfluid Thank you!

  14. outline • Why interesting (BG and other’s work) • Theory part – model, assumptions, equations and prediction • Experiment part – setup, difficulties, data, result and explanation • Conclusion and future work • Acknowledgement

  15. Acknowledgement • Dr. Elizabeth K. Mann • Dr. James C. Alexander • Dr. Andrew J. Bernoff • Dr. J. Adin Mann, Jr.

  16. hole monolayer ẑ 2 r substrate ρ n θ

  17. hole monolayer ẑ r substrate

  18. 4) 5) 8) 44) 45)

  19. 9)

More Related