Neutron and Softmatter

Transcription

1 Neutron and Softmatter Hideki Seto IMSS/J-PARC Center, KEK SOKENDAI

2 So# Ma'er Polymer Liquid Crystal polymeric liquid crystal liquid crystal polymer amphiphilic polymer lyotropic liquid crystal liquid crystal colloid emulsion Surfactant Colloid

3 Common proper.es - large number of internal degree of freedom - weak interaction between structure unit - delicate balance of entropy and enthalpy solid soft matter liquid phase transition

4 Hierarchical structure m

5 Nano-scale Structures in So# Ma'er polymer liquid crystal membrane t~60å d~20å RG~100Å colloids surfactant d~100å l~30å

6 Small-Angle Scattering + qa/2 = nπ q=2πn/a q = k - k q=2k sinθ =2(2π/λ)sinθ Bragg s Law: 2a sin θ = nλ λ ~ 5Å, a~100å θ ~ 1.4

7 Hierarchical dynamics 10 3 R eptation 10 0 CooperativeD iffusion Two-level motion Local motion (β-process) Segmental motion (α-process) d(å) 10 4

8 Inelas.c/Quasi-elas.c sca'ering

9 Surfactants

10 Amphiphilic property hydrophilic hydrophobic water oil

11 Semi-microscopic structures Cubic Inverted Cubic Surfactant Hexagonal Lamellar Cylindrical Micelles Irregular Bicontinuous Spherical Micelles Water Inverted Micelles Oil

12 Spontaneous Curvature depends on packing parameter micelle (oil-in-water) cylinder lamellar reversed micelle (water-in-oil)

13 Packing parameter head-water head-head tail-tail tail-oil

14 Pressure dependence M. Nagao, HS, et al

15 AOT + D 2 O + n-decane 2-phase oil lamellar AOT molecule 1-phase (w/o droplet) water φ spontaneous curvature > 0 water-in-oil droplet 1-phase φ lamellar 2-phase

16 Pressure dependence of SAXS φ s = 0.230, T = 33 C Q(Å -1 )

17 Structure change with P The same as increasing T Pressure tail-tail attractive force increases

18 Why T-effect and P-effect seems to be the same? Temperature counter-ion dissociation Pressure tail-tail interaction

19 Bending energy of surfactant layers W. Helfrich, Z. Naturforsch. C28 (1973) 693 R 2 mean curvature H = R 1 R 2 R 1 Gaussian curvature K = 1 R 1 1 R 2 bending modulus saddle-splay modulus E bend = κ(h 1 ) 2 + κk ds R s spontaneous curvature

20 Neutrons see... deuterated water protonated oil deuterated oil bulk contrast film contrast protonated surfactant

21 Phase separa.on of a water-in droplet AOT 60 AOT / D 2 O / d-decane (film contrast) φ s =0.37 (AOT volume fraction) 40 φ water-in-oil droplet 20 n-decane gel water T( C) Kawabata et al., Phys. Rev. Lett. 92 (2004)

22 Results of NSE experiments Room temperature/pressure T=25 C/P=0.1MPa 1.0 T=43 C/P=0.1MPa I(Q,t)/I(Q,0) I(Q=0.04) I(Q=0.05) I(Q=0.06) I(Q=0.08) I(Q=0.09) I(Q=0.10) I(Q=0.12) I(Q=0.14) t [ns] I(Q,t)/I(Q,0) I(Q,t)/I(Q,0) '0.04' '0.05' '0.06' '0.08' '0.09' '0.10' '0.12' '0.14' t [ns] 10 T=25 C/P=20MPa 'Q=0.05' 'Q=0.06' 'Q=0.07' 'Q=0.08' 'Q=0.09' 'Q=0.095' 'Q=0.10' 'Q=0.11' 'Q=0.12' 'Q=0.13' t [ns]

23 Sca'ering from a shell Expansion of the shape fluctuation into spherical harmonics Huang et al. PRL 59 (1987) Farago et al. PRL 65 (1990) R(θ,φ,t) = R 0 {1 + a nm (t)y nm (θ,φ )} nm up to n=2 mode gives damping frequency of the 2nd mode deformation I(Q,t)/ I(Q,0) = exp[ D eff Q 2 t] 2 5λ 2 f 2 (QR 0 ) a 2 D eff = D tr + Q 2 2 [4πf 0 (QR 0 ) + 5 f 2 (QR 0 ) a 2 ] mean-square displacement of the 2nd mode deformation n=0 mode n=2 mode translational diffusion shape deformation where f 0 (QR 0 ) = [ j 0 (QR 0 )] 2 f 2 (QR 0 ) = 5[4 j 2 (QR 0 ) (QR 0 ) j 3 (QR 0 )] 2

24 T- and P- dependence of the bending modulus T ( C) P (MPa) 40 60

25 T- and P-effects on an ionic surfactant monolayer Temperature Pressure

26 Possible application -pressure antagonism of anesthesia -deep sea organisms -food processing

27 Lipids

28 Cells and Vesicles cells GUV Giant Unilamellar Vesicle cell-sized liposome 10 μm bio-membranes phospholipid bilayers 10 μm lipid molecule hydrophillic part hydrophobic part

29 Lamellar structure of lipid bilayers phospholipid lamellar structure ~60Å bilayer multilamellar vesicles scale [m]

30 Phase transi.ons of lipid bilayers

31 Neutron vs X-ray neutron x-ray dynamical behavior static structure bending modulus

32 NSE measurements on lipid bilayers N. L. Yamada, HS, et al DPPC/CaCl2/D2O (DPPC: 4wt%, CaCl2: 7mM) d~1000å wt.% I(q,t)/I(q,0) 0.8 Considered as a single membrane fluctuation q=0.040 q=0.050 q=0.060 q=0.075 q=0.090 q=0.110 q= Fourier Time [ns]

33 Single membrane fluctua.on A lateral length L along the membrane flat surface is perturbed in some way, because they are 2D connected object. h L ~ (k B T/κ) 1/2 L ζ roughness exponent: ζ = 1 (2D object) = 3/2 (1D object) ~ (κ/k B T) 1/2 ζ Q -1/ ζ The Stokes-Einstein diffusion coefficient is, D(Q) ~ (k B T/ηL) ~ (k B T/η)(k B T/κ) 1/2 ζ Q 1/ ζ The relaxation rate is, ~ Γ(Q) D(Q)Q 2 ~ (k B T/η)(k B T/κ) 1/2 ζ Q 2+(1/ ζ) Thus they obtained the stretched exponential form of the relaxation function as, I(Q, t )= exp[-(γ(q)t) β ] where Γ(Q)= γ α γ κ (k B T) 1/ β κ 1-(1/β) η -1 Q 2/β with β = 2 / (2+1/ζ) = 2/3 (2D object) = 3/4 (1D object) γ κ = 1-3 ln(ξ / l(t)) k B T / (4πκ) γ α = (2D object) = (1D object) Zilman and Granek Q // z undulation amplitude: h = 1/Q lateral length: L

34 NSE results wt.% I(q,t)/I(q,0) q=0.040 q=0.050 q=0.060 q=0.075 q=0.090 q=0.110 q=0.130 Γ(q) [ns -1 ] wt.% 4wt.% 6wt.% 8.53wt.% 12wt.% Fourier Time [ns] q[å -1 ] 0.1 2/3 I(q,t)=I(q,0)exp(-(Γt) ) Γ=Aq 3 3/2 2 Kc=(γ α γ κ (kbt) /Aη) Kc:bending modulus γ α =0.025 : 2D membrane η: viscosity of D2O γ κ =1 : Kc >>kbt

35 T-dependence of bending modulus T / C gel phase liq. cryst. phase present result C-H Lee, PRE TM

36 Anomalous swelling above T M DMPC+KBr DMPC

37 NSE results 2/3 I (q,t)/i (q,0)=c exp[-(γt) ]

38 Bending modulus NSE, 2007 SAXS, 2005 So#ening Thermal fluctua.on increases Repeat distance increases

39 Our interpreta.on irregular stacking of bumpy layers thickening & hardening

40 Possible application Inhibitory Effects of Hybrid Liposomes on the Growth of Tumor Cells HL induces apoptosis of tumor cells

41 D2O

42 d-dmpc

43 water

44 QENS with Incoherent Scattering rotation coherent incoherent translation vibration van Hove function Fourier trans. 44

45 Purpose of this study Dynamical behavior of water molecules is investigated with QENS Wide energy range / high energy resolution Available to measure from free water to hydrated water Fully deuterated phospholipid QENS signal from hydrophlic part could be neglected and the dynamical behavior of water molecules can be estimated Sample: d 67 DMPC + H 2 O

46 Samples d 67 DMPC-37H 2 O Coherent scatt. Incoherent scatt. d 67 DMPC barn (8.5%) barn (7.3%) 37H 2 O barn (3.9%) barn (80.3%) DMPC-35D 2 O Coherent scatt. Incoherent scatt. DMPC barn (5.5%) barn (84.5%) 35D 2 O barn (7.9%) barn (2.1%) Sample can 14mm-φ / 40mm-h / 0.5mm-t (double cylinder)

47 Experimental Elastic Scan K, 1 Kmin -1 ) Quasi-Elastic Neutron Scattering d 67 DMPC-37H 2 O: 316, 305, 295, 285, 275 K (12h / Temp) -0.5 ΔE 0.5 (mev), δe Reso = 3.6 µev, at 3 chopper settings DMPC-35D 2 O: 306 K ΔE 0.1 (mev), at 1 chopper settings 47

48 Elastic Scan pre-transition(t pre ) main-transition(t tr ) melting of water lipid bilayers water water + hydrocarbon chain 48

49 QENS data of d 67 DMPC-37H 2 O dynamics of water molecules Quasi-Elastic Neutron Scattering was observed and its width increased with increasing temperature. 49

50 Model Analysis free water loosely bound water tightly bound water fast dynamics slow 3 modes are assumed to analyze the observed QENS data 50

51 Liquid Crystalline Phase (T = 316, 305, 295) { A L ( Γ, E) + A L ( Γ, E) + A L ( Γ, Q) } R( Q, E) BG S Q, E) = + ( Tight Tight Tight Loose Loose Loosely Free Free Free 51

52 Ripple Gel Phase & Gel Phase (T = 285, 275 K) Tightly bound water is too fast to observe (the width is less than the resolution function). { A ( E) + A L ( Γ, E) + A L ( Γ, Q) } R( Q, E) BG S Q, E) = + ( Tightδ Tight Loose Loose Loosely Free Free Free 52

53 Q 2 dependence of HWHM Tightly bound water Simple diffusion model (Fick s law) Γ Tight = DQ 2 < l > 53

54 QENS data of DMPC-35D 2 O Dynamics of lipid molecules { A ( Q) L ( Γ, E) + A ( Q) L ( Γ + Γ ), E) } R( Q, E) BG S Q, E) = + ( Trs Trs Trs Int Int Lat Int A model assuming lateral diffusion of lipid molecules within bilayer and internal mode of a lipid V. Sharma, et. al, J. Chem. Phys. B, 119 (2015),

55 Arrhenius plot of diffusion const. Activation energy [ kjmol -1 ] Free water 10.5 ± 1.2 Bulk water 18.6 ± 0.3 Activation energy of Free water is less than that of bulk water Free water: diffusion constant is the same order as that of bulk water Loosely bound water: 1 order less diffusion constant than that of free water Tightly bound water: the same diffusion constant as that of DMPC 55

56 Arrhenius plot of mean res. time Activation Energy [ kjmol -1 ] Free water 19.0 ± 2.5 Bulk water 28.9 ± 1.0 Loosely bound water 27.5 ± 3.2 Free water: mean residence time is the same as that of bulk water Loosely bound water: 1 order of magnitude more than that of bulk water 56

57 Arrhenius plot of jump distance Jump distance of the loosely bound water is longer than that of bulk water hydrogen bonding distorts from the normal water structure 57

58 Coefficients of 3 components A 0 s are proportional to the number of atoms. 58

59 Number of water molecules N Tight = A 0Tight + A A 0Tight 0Loose + A 0Free f DMPC R 1 f DMPC N N Loose Free = = A A 0Tight 0Tight + + A A A A 0Loose 0Loose 0Free 0Loose + + A A 0Free 0Free R 1 f R 1 f DMPC DMPC R = 37 (water molecules/lipid molecule) f DMPC = Incoherent scatt. fraction of DMPC) Free water: almost constant Loosely bound water: increase with increasing temperature Tightly bound water: decrease with increasing temperature 59

60 Summary free water 24 molecules: no T dependence nearly bulk water, but confinement effect loosely bound water 8-12 molecules: increase with T slow dynamics: 1/10 of free water tightly bound water 7-2 molecules: decrease with T move with lipid molecules 60

61 Possible application bio-compatibility and bound water layer

62 Hardcover: $ E-Book: $145.99