Soft Nanopolyhedra. Jiunn-Ren Roan. Department of Physics National Chung Hsing University Taichung, Taiwan

Transcription

1 Soft Nanopolyhedra Jiunn-Ren Roan Department of Physics National Chung Hsing University Taichung, Taiwan

2 Polymers as flexible chains PE PS PMMA PEO, PEG PDMS From P.-G. de Gennes, Scaling Concepts in Polymer Physics, Cornell University Press, Ithaca (1979).

3 10 ~ 50 nm From P.-G. de Gennes, Scaling Concepts in Polymer Physics, Cornell University Press, Ithaca (1979).

4 Structured planar brushes Binary brush Ripple phase Dimple phase Dimple phase From M. Müller, Phys. Rev. E65, (R) (2002).

5 Real structured planar brushes From S. Minko et al., Phys. Rev. Lett. 88, (2002).

6 What if the substrate is a nanoparticle?

7 Spherical polymeric assemblies Typical polymer size: 10 ~ 50 nm Micron-sized particle Nanoparticle Planar assemblies Spherical assemblies

8 Real spherical polymeric assemblies Dendrimers From A. W. Bosman et al., Chem. Rev. 99, 1665 (1999).

9 From A. W. Bosman et al., Chem. Rev. 99, 1665 (1999).

10 From A. W. Bosman et al., Chem. Rev. 99, 1665 (1999).

11 Effect of spherical geometry? + = or or something else? watermelon hot air balloon

12 Model J.-R. Roan, Int. J. Mod. Phys. 18, 2469 (2004), Phys. Rev. Lett. 96, (2006). f A, N A, b A f B, N B, b B R v AS, v BS, v AB v = 0, miscible v = 1, immiscible

13 Edwards model for polymers A polymer chain A random walker Self-consistent field (SCF)

14 Binary spherical brush n=0 G ( r, n) κ r G (, N n) κ r κ n= N ±

15 Self-consistent-field equations

16 Solving the (3+1)-D SCF equations 1. Discretization: 2. Imposing periodicity:

17 Solving the (3+1)-D SCF equations 3. Modified alternating direction implicit method (ADI): unconditionally stable locally second-order correct in space and time solvable tridiagonal algebraic systems ADI nonlinearity modified ADI 4. Iteration until self-consistency is obtained

18 System types: A-S system, v AS = 1 Parameters A-B-S system, v AB = 1, v AS = 0, v BS = 0 (good solvent) A-B-S system, v AB = 1, v AS = 0, v BS = 1 (selective solvent) Grafting sites: uniform: gradient 1: gradient 2: step:

19 Discretization parameters: N r = 25~35 N θ = 24~32 N ϕ = 48~64 Δn = 0.1, N κ = 10~30; N n = 100~200 System parameters: b κ = 1 R = 4 N κ = 10, 15, 20, 25, 30 N r N θ N ϕ 30,000~70,000 f A /f B = 150/30, 120/60, 90/90, 60/120, 30/150; 100/20, 80/40, 60/60, 40/80, 20/100; 50/10, 40/20, 30/30, 20/40, 10/50

20 Results!

21 A-S system; uniform A

22 N A =30, f A =8 in a poor solvent

23 A-B-S system in a solvent good for A and B; uniform A and B

24 NA=30, NB=30, fa=120, fb=

25 N A =30, N B =30, f A =120, f B =60 N A =30, N B =25, f A =120, f B =60

26 N A =30, N B =30, f A =120, f B =60 N A =25, N B =25, f A =120, f B =60

27 N A =25, N B =25, f A =90, f B =90 N A =15, N B =15, f A =90, f B =90

28 N A =30, N B =30, f A =30, f B =30 N A =30, N B =25, f A =30, f B =30

29 f A /f B 150/30 L BA L BA 140/40 ICO/B 120/60 ICO/B Z8/B 90/90 R L AB R R ICO/A ICO/A 60/120 L AB 30/150 ICO/A L AB N A =20, N B =20 N A =30 N B =30 N A =30, N B =25 N A =30, N B =20 N A =30, N B 15

30 N A =30, f A =120, f B =60 N B 30 ICO/B Re-entrance transition 25 Z8/B 20 ICO/B 15 L AB

31 How are the islands arranged?

32 Science 301, 483 (2003).

33

34 Z6: N A =30, N B =25, f A =30, f B =30

35 Z8: N A =30, N B =25, f A =120, f B =60

36 Z9: N A =25, N B =25, f A =80, f B =40

37 Z10: N A =25, N B =20, f A =120, f B =60

38 Z12(ICO): N A =20, N B =20, f A =120, f B =60 From:

39 A-B-S system in a solvent good for A and B; non-uniform A or B

40 N A =20, N B =20, f A =120, f B =60 A: uniform; B: uniform N A =20, N B =20, f A =120, f B =60 A: uniform; B: gradient 2

41 N A =20, N B =20, f A =120, f B =60 A: uniform; B: gradient 2 N A =20, N B =20, f A =120, f B =60 A & B: gradient 2

42 N A =25, N B =25, f A =60, f B =60 A & B: gradient 2 N A =15, N B =15, f A =60, f B =60 A & B: gradient 2

43 Giant-clam (GC) structure Credit: Lioneltimalistair/Science Photo Library Credit: Georgette Douwma/Science Photo Library

44 N A =15, N B =15, f A =60, f B =60 A & B: gradient 2 N A =30, N B =30, f A =30, f B =30 A & B: gradient 2

45 N A =25, N B =25, f A =60, f B =60 A & B: gradient 2 N A =25, N B =25, f A =60, f B =60 A: gradient 1; B: uniform

46 A-B-S system in a selective solvent; uniform A and B

47 N A =20, N B =20, f A =120, f B =60 in a solvent poor for A but good for B

48 N A =20, N B =20, f A =120, f B =60 in a solvent good for A but poor for B

49 N A =20, N B =15, f A =120, f B =60 in a solvent poor for A but good for B

50 N A =20, N B =15, f A =120, f B =60 in a solvent good for A but poor for B

51 N A =20, N B =10, f A =120, f B =60 in a solvent poor for A but good for B

52 N A =20, N B =10, f A =120, f B =60 in a solvent good for A but poor for B

53 Applications?

54 Nanostructured Nanoparticles

55 Nature Mater. 3, 330 (2004). Binding of mercaptopropionic acid (MPA), HOOC (CH 2 ) 2 SH and octanethiol (OT), CH 3 (CH 2 ) 7 SH on a gold nanoparticle.

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57 What might have happened... surface-induced structures N A =25, N B =25, f A =60, f B =60 A: southern hemisphere; B: homogeneous

58 Smart Drug Carriers

59 J. Am. Chem. Soc. 127, 6248 (2005).

60 Self-assembly of Structured Particles (Chemistry of Colloid Molecules )

61 Nano Lett. 4, 1407 (2004). 2π/5 2π/6

62

63

64

65 Fabrication of Multivalent Nanoparticles

66 Nature 437, 664 (2005).

67

68 JACS 127, (2005).

69 Biomolecular Recognition and Templation/Catalysis

70 Chem. Commun. 2005, 303 (2005). Mixed Monolayer Protected Cluster

71

72 Discussion A pure mathematical problem: Packing on a sphere Thomson s problem, Tammes problem, VSEPR, etc. A practical technical problem: Nanostructured nanoparticle Atoms for multivalent chemistry of colloids, templates for materials with hierarchical structure, etc. What do we need to know? N A, N B, f A, f B, and interaction parameters v AB, v AS, v BS.

73 Acknowledgment Prof. Toshihiro Kawakatsu (Tohoku University) 川勝年洋 Dr. Hiroya Kodama (Mitsubishi Chemical Co. Ltd.) 樹神弘也 Mr. Guo-Hau Huang (National Chung Hsing University) 黃國豪 National Science Council, Taiwan National Chung Hsing University, Taiwan