MODERN PROBLEMS OF POLYMER PHYSICS

Prof. Andrey V. Lezov

Saint-Petersburg State University Department of Polymer Physics Ulyanovskaya str., 1, St.-Petersburg, 198504 Russia

[e-mail]

POLYMERS

Polymer networks

Rod-like conformation

The contour length L is increased

Coil-like conformation

A -Kuhn segment <h2>=NA2 length

<h2>=LA

FLORY’S THEORY

Free energy of polymer molecules:

	F Fel Fint
	h2	F	N	N
				hd
	Fel N	int

	F h2	N2	h N ;	3
				d 2
	N	hd

h2 1/2 N3/5A;d 3

h2 1/2 N3/4A;d 2

h2 1/2 NA;d 1

h2 1/2 N1/2A;d 4

Polymer coil in a good solvent	c~N-4/5
Polymer coil on substrate
Polymer coil in ideal conditions;	c~N-1/2

GLOBULAR CONFORMATION OF THE POLYMER CHAIN

F Fattr Frep

c(r)~1/r for ideal coil

F	V N2	;	c(r)
rep	hd

Fattr N lnh

F 0h

h N1/3

c=const for polymer chain in globular conformation

r

Core

Shell

MOLECULAR

HYDRODYNAMIC METHODS

m e t h o d s

v i s c o s i m e t r y				is o t h e r m a l d if f u s io n				v e lo c i t y s e d im e n t a t i o n

in t r in s ic v is c o s it y

[ ]~R3/M

t r a n s la t io n d if f u s io n c o e f f ic ie n t D ~ 1 / R

c o e f f ic ie n t o f s e d im e n t a t io n S ~ D M

MD		MSD

{A, d}

ISOTHERMAL DIFFUSION METHOD

to = 0 t > to t

board	Solution	L
Artificial

ns no

Solvent

L=-D(dc/dx)

c/dt = - L/ x

dc/dx=0

c/ t = D 2c/ x2

D=kT/(6πηoR)

<σ2>=2Dt

D

1

P1

P2

K D2

/2	Diffusional cell

ANALYTICAL ULTRACETRIFUGE

Vp=sfm; D=s( / c)

=kT(c/M)

S~DM

Svedberg ultracentrifuge

MOLECULAR OPTICS

METHODS

m e t h o d s

D L S				E le c t r ic b ir e f r in g e n c e			F lo w b ir e f r in g e n c e
lig h t s c a t t e r in		g
D ~ 1 / R				K e r r c o n s t a n t K			o p t i c a l s h e a r c o e f f i c i e n t
M w				r e l a x a t i o n t i m e s
R g

K(M) ,

(M) F, A

n/ a

A