Possibility of microphase separation in polyelectrolyte systems

Polymer Science U.S.S.R. Vol. 32, No. 5, pp. 852-861, 1990 Printed in Great Britain.

0032-3950/90 $10.00 + .00 © 1991 Pergamon Press plc

POSSIBILITY OF MICROPHASE SEPARATION IN POLYELECTROLYTE SYSTEMS* I. A. N Y R K O V A , A. R. KHOKHLOV and YE. Y u . KRAMARENKO Lomonosov State University, Moscow

(Received 30 November 1988)

The stability of the homogeneous state of a mixture of two polymers one of which is a weakly charged polyelectrolyte is considered. At low concentrations of the charged polymer the spinodal breakdown of such a state occurs with the formation of microphasically separated structures. In some cases such structures may persist in the equilibrium state. The effect of a low molecular mass salt on the properties of the system considered is analysed. The effect of improving the compatibility of the mixture of two polymers on charging one of the components on addition of a salt becomes relatively less marked although to strong salt concentrations it remains very significant. At a salt concentration of the order of that of the counter-ions of the polyelectrolyte chains microphasic structuring completely disappears and spinodal breakdown occurs into the macroscopic homogeneous phases.

IN REFERENCE [1] the effect of improving the compatibility of blends of two polymers was theoretically predicted and established experimentally when a small fraction of the charged units was introduced into the chains of one of the components. Theoretical analysis was made for a very simple case: for a salt-free solution or the polymer melt the spinodal corresponding to layering into two homogeneous macroscopic phases was investigated. In the present work this analysis is generalized in two respects. Firstly, we shall consider the general case when the system has a certain concentration of the low molecular mass salt. Secondly, we shall explore the stability of the system not only in relation to separation into homogeneous phases but also in relation to microphase separation. The last posing of the problem is linked with the prediction of ref. [2] that in a similar system (solution of a weakly charged polyelectrolyte in a poor solvent) microphase separation must be observed. We shall show that in certain conditions this may also occur in a mixture of two polymers one of which is weakly charged. The structures thereby formed must be similar to those obtained on microphase separation of block copolymers although the physical cause of their formation is quite different. These structures are extremely labile and may readily rearrange themselves with change in the external conditions (ionic strength, quality of the solvent, temperature, etc.). Therefore, experimental attempts to detect the effects predicted in the present work are of some interest especially in terms of obtaining materials with a controllable and readily variable microstructure.

Free energy of the heterogeneous state. We shall consider a system which has two polymeric components---weakly charged polyelectrolyte (A) and a neutral polymer (B) and also several kinds of low molecular mass ions including counter-ions formed as a result of dissociation of the polyelectrolyte units. To simplify the theoretical analysis we shall assume that the low molecular mass solvent is absent from the system. The intrinsic volume of the low molecular mass ions is *Vysokomol. soyed. A32: No. 5,918--926, 1990.

852

Microphase separation in polyelectrolyte systems

853

negligibly small and these ions themselves have an identical affinity for both polymers and dissociation of the "charged" units of the polymer A is complete. Analysis shows that these assumptions in essence do not limit generality since allowance for the corresponding factors, for example, the presence of a low molecular mass solvent, leads only to renormalization of some parameters but not to change in the qualitative character of the results. To investigate the stability of a system in relation to microphase separation the first need is to write the free energy F o f its heterogeneous state (i.e. the state in which the concentrations of all the components change from point to point). As in ref. [1] we shall make the analysis within the Flory-Huggins lattice model in the self-consistent field approximation. Then the expression for F may be written in the form [1-3]

F/T = - ( x / a 3 ) f ~2(r) d3r + (1/NA a 3) f ~ ( r ) I n ~(r) d3r +(llNna3) f [1-dp(r)]ln[1-~(r)]d3r+ ~ fn~(r)lnn~(r)d3r+ Fp/T+ FelT,

(1)

where ~(r) is the volume fraction of the polymer units A at the point r (respectively 1 - ~(r) volume fraction of units B); n~ (r) is the concentration of the low molecular mass ions of the a kind at the point r; NA and NB are the number of units in the chains A and B, respectively; X is the Flory-Huggins parameter of the interaction of the components A and B; a is the size of the unit and simultaneously the period of the lattice in the lattice model; T is temperature which here and hereafter is expressed in energy units. The first term in the sum (1) is the energy of the non-electrostatic interactions of the units A and B and the following three terms the free energies of the translational motion respectively of the chains A, the chains B and the low molecular mass ions. The term Fp/T describes the specifically polymeric contribution to the free energy associated with entropic losses from the uneven distribution of the concentration of the units of the chains A and B [4]:

Fp/T= (1/6a) f

[V (~(r))1/212 d3r + (1/6a) f [V (1 - ~ ( r ) )1/212d3r.

(2)

The expression for Fp may be written in the form of formula (2) only when the characteristic scale of the heterogeneities in the system K -1 far exceeds a. This will also be assumed here and everywhere below. Of course, formula (2) for Fp/T is strict only in presence of strong heterogeneities in the system k-l<,aNi 1/2, i = A, B [4]. However, we shall use it in the whole region k - l ~> a since for k - l ~> aNi 1/2 the terms in formula (2) become insignificant as compared with the terms 1

Nia3~i ln~i in the sum (1) [see formula (16) in which these expressions correspond to the terms

k2a2/12cbiand

1/~iNi]. The last term in expression (1) Fe/T is linked with the free energy of the electrostatic interactions. We shall consider that each ruth unit of the polymer A bears an elementary charge e, with m ~>1 (of course, m < NA) so that increase in the rigidity of the chains A through electrostatic interactions does not occur [according to ref. [5] for this there must be e2/eT,~am1/2,where e is the dielectric constant of the medium; this inequality follows from the condition (7) introduced below and required for the applicability of the theory outlined]. For this system the magnitude Fe/T is calculated in ref. [6] and the result has the form

I . A . NYRKOVAel aL

854

eJr= f j(p(r)p(r')i d3rd3r ' n,~(r)Z,~ +~--~-a3)

d3r,

(3)

where p(r) is the density of the charge at the point r p(r) = ~ 3 ~(r) + e ~ n,~ (r) Z,~

(4)

a

(Z,, is the valency of the ions of the a kind). In formula (3) the first term in the right-hand part describes the usual Coulombic interactions in a system with distributed charge density p(r) and the second is a natural generalization of the Debye-Htickel formula for the free energy of classical electroneutral plasma [7]. Below we shall investigate only the weakly heterogeneous states of the system and, therefore, in writing expression (3) the permeability of the medium e may as a first approximation be considered constant [allowance for the inconstancy of e would lead to the appearance of additives cubic in ~,~ and P to the resolutions of (10) and (14)]. For similar reasons only the "averaged" [see formula (13)] screening radii u 2 and x,~2 will figure in formulae (12), (14) and (16). The functions ~(r) and N,~ (r) in expressions (1)-(3) cannot be considered independent and are linked by the condition of the general electroneutrality of the macroscopic regions. To write this condition we denote as ~(r) and ~?, respectively the variable and constant components of a certain function ~(r) [the role of this function may be played by ~(r), n,~ (r), p(r), etc.], i.e. 1! ----p

y(r) d3r,

~(r) --- y(r) - ~?,

(5)

where V is the volume of the system. Then the condition of electroneutrality assumes the form ~ e =--dP/a3m + Z ~ Z~ = O.

(6)

a

Thus, in the expression for the free energy determined by the formulae (1)-(6) the theoretical approaches usually employed to describe salt-free polyelectrolyte solutions are brought together (allowance for the free energy of the translational movement of the counter-ions and the total electroneutrality of the macrophases [1, 8] with the approaches describing the interaction of charged objects with dominance of the low molecular mass salt over the counter-ions (within the Debye-Hiickel classical theory [2, 9, 10]). We shall assume that the usual condition of applicability of the Debye-Hiickel theory is fulfilled for the system considered by us in this work [7] e2/e Trn "~ 1,

(7)

where rn is the Debye radius (averaged over the whole volume of the system) and also the condition limiting the scale of the charge heterogeneity

E

(8)

a

where ~ is the variable part of the charge density of (4) [the inequality (8) in essence does not limit the generality of the discussion since in study of the stability only slight deviations from the

Microphase separation in polyelectrolyte systems

855

homogeneous state are significant]. In this case, as shown in ref. [6], the second term in the sum (3) adds up to an insignificant constant.

Condition of stability. To investigate the stability of the system considered in relation to microphase separation it is necessary to determine whether the functions ~ ( r ) - - ~ , n,~(r)--ria (matching the homogeneous state) correspond to the local minimum of the functional (1) F{~(r), na (r)}. Only in this case will the homogeneous state be stable. Thus we consider change in the free energy of (1) for minor deviations of the functions ~(r) and na (r) from the • and tia values characteristic of the homogeneous state, (I ~1 ~ ~, Iha I ~ ha). For this we resolve the functional F{~(r), na (r)} into a series with an accuracy to quadratic terms for the small variable components (~, h,,, iS) (we immediately omit the variable part of the second term in formula (3), using the result of ref. [6]) and perform the Fourier transformation for the functions • (r), ha (r), ~(r), i.e. we pass from y(r) to 1

3,(k) = (2zr)3 f e -ikr y(r) d 3 r.

(9)

We then obtain 1 ] TL [-2x+ 4 (1 -- ~))NB

F/r=(F/r)const + (2703 ~ 1

× f4,(k),b(_k)d3 k + y~,,lna f h"(k)tia(-k)d3k

+__1{! _1 )fk2(i)(k),(_k)d3k+4'n"e r J(/~(k)~(-k) 1 2 a \ ~ +1 • k2 d3k'

(10)

where k-= Ikl and the term (F/T)const is the free energy of the homogeneous state 1 ~ l n ~ + _ _NB l (l_~)ln(l_~)] (r/T)const = V { ~ [ -X~2 + NA +

Yhalnti~

2 "n'l/2e3 ( ~ ) 3 (eT) 3/2 h'~Z'~2+6P/ma3\3/2"

(11)

ct

As noted the functions ~(r) and na (r) [and hence also ~(k)] and na (k) are not independent. Their constant components are linked by the condition (6). A link also exists between the variable components---the small counter-ions "align themselves" to the given distribution in the space of the polymeric substance ~(r). To determine this link it is necessary to find the set of functions {ha (k)}, minimizing the functional (10) for the set function ~(k). Using the definition of (4) and equating to zero the variation derivatives of expression (10) in respect of n~ (k) we get

Xa2 (i)(k) Zaha(k)=

k2+x2 ma 3 ,

(12)

where ~,2 and x 2 are the analogues of the classical parameter of Debye-Hiickel screening ~a 2--~

4~re2

eT

naZa 2,

X2~- ~'~ ~a 2 = 1/ro 2.

(13)

We would note that if in the resolutions of type (10) the variable part of the second term of the

I . A . NYRKOVAet al.

856

sum (3) is taken into account this will lead instead of expression (12) to the following linear set of equations in respect of {n,~(k)):

4*re2z'~(\ma

+ ~ = V~r

~'Z°h~)/k2

e3 z~ 2 X~z~ 2e~,

In absence of the right-hand part, this system is equivalent to equations (12) and (13). The corrections to n~ (k) associated with the presence of the right-hand part (assuming the smallness of this right-hand part) have the relative order <~e21eTro. Therefore, if the condition (7) is fulfilled the second term of the sum (3) is actually unimportant for investigation of the stability of the system relative to spinodal breakdown. Substituting the relations (12) in the equality (10) gives

F / T = (F/T)const+4*raf{~[-2X+~ANA + (1 1 ) N B ] k2

1

1

4zr

e

2

1

3

The fact that the sum of the second and fourth integrals in formula (10) was reduced to the last term in expression (14) means that in formula (1) instead of the terms corresponding to the translational free energy of small ions and the energy of Coulomb interaction, one may write the term

__L_ 1 (_L_ e ~2 r f *(r)e(r') 2eT\ma3] j j ~ _ - ~ exp[-x[r-r'l]dard3r '.

(15)

This term describes both the direct electrostatic interactions and the "alignment" of the small ions to the distribution q~(r). It matches the known expression of the Debye-Hiickel theory [7]. The conclusion presented thus shows that this expression may be used in the general case and not only when the number of ions of the salt far exceeds the number of counter-ions [the determination of x is given by the formula (13) including summing on an equal footing both for counter-ions and the ions of the low molecular weight salts added]. For the homogeneous state of the system considered to be stable the expression in braces in formula (14) must be non-negative (a similar problem was investigated in ref. [11]), i.e. the inequality

k2a2 [1

1 \ +

[ +

1 +

+

1 o-,)~

]

4~ru

1

J + mY (k2 + ~ ) a ~ > 0 '

(16)

must be fulfilled where the standard notation

u =-e2/eaT

(17)

is used.

Results and their discussion. Now let us investigate the inequality (16) for different values of the parameters of the task. For determinancy we shall assume that the system has only one type of monovalent low molecular mass salt of concentration ns. In this case according to the formula (13) 4*re2 ( ~ ) x"2 = " ~ ~ + 2ns •

(18)

Microphase separation in polyelectrolyte systems

857

Violation of the inequality (16) for k = 0 signifies the instability of the system in respect of spinodal breakdown into macroscopic phases. In particular, for k -- 0 and in absence of an extra low molecular mass salt the condition (18) passes into the result of ref. [1]. If the inequality (16) is fulfilled for k = 0 but is violated for k 4:0 this means that in the system spinodal breakdown must occur with the formation of a microphase structure. From relations (16) and (18) it follows that the critical value of the parameter X for which breakdown into macrophases occurs is written thus:

Xcr(O)

~---

1 1 1 2+----~A -~ 2(1 -- ~)NB + 2m(~ + 2ma3ns) "

(19)

The formula (19) generalizes the result of ref. [1] to the case when there is a concentration of salt ns differing from zero. From this formula it will be seen that on addition of the salt the effect of improvement of the compatibility of the mixture with increase in the degree of charging of the chains A becomes less marked. However, to salt concentrations n s a 3 - N / m z ( N / m times greater than the characteristic concentrations of counter-ions) this effect remains very substantial. With increase in the parameter X, i.e. incompatibility of polymeric components, the inequality (16) may, however, for the first time cease to be fulfilled for k ¢: 0. Analysis shows that this occurs for 2n~ ma 3 + + < (3~(1 - ~)Hru)1/2.

(20)

In this case the homogeneous phase loses stability in respect of the microphasic mechanism. The value of the wave vector k0, for which the inequality (16) is violated for the first time, is expressed as k°Za2= 4"~ ' u lL\ ( 3 d Pr ~ru ( 1 - ( b ) ln/' / 2 - ( b - 2 n s m a 3 ]

(21)

Accordingly, the spatial scale of the microphase structure appearing on spinodal breakdown will be of the order 27r/ko. This takes place when the parameter X reaches the critical value 1 1 1 "flU [2(3~(1 -- ~))1/2 1 Xcr = 2~----~A+ 2(1 -- ~)NB + ~m ~(1 -- ~P) I_ \ ~'u -- dp -- 2nsma 3 .

(22)

It is easy to show that on fulfillment of the inequality (20) Xcr < Xcr(°). We would note that here k0 -1 >>a (21), i.e. the writing of (2) is correct. In fact, for the usual condition of applicability of the Debye-Hiickel theory [7] to be fulfilled for all • (including also for + - 1 ) the inequality: u ~ m 1/3 must be satisfied. From this it follows that ko2a2"~m-5/6~l for M>>I [since according to the formula (21) ko2a2~

I . A . NYRKOVAet al.

858 X.lo ~

• ~1..\.

~\

(a)

)1

,-\, -

I

f

I

I

I

I

I

I

I

I

{

,'i'll ~ ~, -~,..-1

i ,,',",:,-\ -

~1~ . '1

"

. . . . .

I

o.a

I

~

I

aa

FIG. 1

(Koa)2.10 t 2.10-2

0

q~

o.~ ~ I

I

I

e/,

I ~ 0.It \ il\

\t\

O.8

FIo. 2

FIG. 1.

Spinodals for macro- and microphase separation: the functions )t'c,(°)(~) (continuous curves) and

Xc,(~) (dashed lines) calculated from the formulae (19) and (22) for NA = Na = 103. Dotted line is the spinodal for the uncharged polymer A. Here and in Fig. 2: a, ns = 0, u = 1, the values of the parameter 1 / m are entered above the appropriate curves; b, m = 100, u = 1, the n s a 3 values are entered above the appropriate curves (for n ~ a 3 = oo the salt completely neutralizes the charges on the chains A); c, ns = 0, FIG. 2.

m = 100, the u values are entered above the appropriate curves. Dependences of (koa) 2 on @ calculated from the formula (21) for NA = Nn = 103.

charging of the chains A (any value of m) always intersect the abscissa axis in line with the formula (21) at the points ~ = 0 and • = ~* where

Microphase separation in polyelectrolyte systems

859

~* = (1 + ~ru/3)-1

(23)

(Fig. 2a). Thus, in this case for • < ~* spinodal breakdown of the homogeneous phase with increase in the parameter X begins by the microphase mechanism; if • > ~* the usual spinodal breakdown into two macrophasic phases occurs. As follows from Fig. lb, with rise in the concentration of the low molecular weight salt ns the critical values of X decrease, i.e. the effect of improvement of compatibility weakens. From Fig. 2b, it will be seen that the characteristic scale of microphase separation k0 -1 increases but the region corresponding to spinodal breakdown by the microphasic mechanism sharply narrows with the appearance of the boundary of this region not only on the side of high but also low concentrations. The region of microphase structuring completely disappears for

ns** = 41a3 [( i +-~u) 1/2- 1 ] [for the values of the parameters in Fig. 2b, the formula (24) gives ns**a3~ of the mixture ~** at the point of disappearance is given by the formula ~**

111-(1+3] -1'2]

=_

2

~-~u/

j

(24)

10-3]; the composition

(25)

We would note that for u ~>1 [the evaluation u ~ 1 is obtained, for example, for values of the parameter a ~ 7/~, e ~ 8(k--formula (17)] according to relations (24) and (25), ns** ~ 4i**/ma 3. This means that the disappearance of the region in which spinodal breakdown occurs with microphase structuring requires that the concentration of the low molecular mass salt be of one order with that of the counter-ions. In the case u <~1, from formulae (24) and (25) we similarly obtain n s * * - u -1/2 i.e. the concentration of the salt must become times greater than that of the counter-ions. Finally, from the graphs in Figs lc and 2c, it may be concluded that with fall in the parameter u the region of microphase structuring heavily increases. The values decrease but the Xcr(°) values remain unchanged; in the region of small volume fractions of the charged polymer ( ~ ~ 1) with fall in u the characteristic k0 values also decrease (increase in the scale of microphase separation). Thus, it may be concluded that in the system containing the charged polymer A and the neutral polymer B spinodal breakdown in many cases (especially for low polymer A concentrations) occurs with the formation of microphasically separated structures. The physical cause of this is similar to that for which in the system considered compatibility improves [1]: separation into macroscopic phases is disadvantageous because of the heavy loss of translational entropy of the counter-ions while on formation of the microphases this factor is not so great and the gain in the energy of interaction of the units is quite considerable. We are, in fact, considering a microphasically separated structure with weak heterogeneity in the distribution of the polymer substance: ~(r) = ~0 sin (kr). The gain in the energy of interaction is determined only by the value I~0 [ and does not depend on the period of the resulting structure k - 1 [terms of the form c o n s t ( k ) f ~ ( k ) ~ ( - k ) d 3 k in the formulae (10) and (14)]. The other terms in formula (10) depend on k: the contribution of

dP**/ma3,

u-1/2

Xcr

1

860

I . A . NYRKOVAet al.

originating from the entropy of the translational movement of small ions in line with expressions (12) diminishes with rise in k as 41ru

u2

ms

)2a2 I ol

the term originating from the items of (2) rises as 1 • (1-~)

k2a 2 --

12

1

ol2;

the last integral in formula (10) corresponding to Coulomb interactions of (3), also increases with rise in k as 47ru k2 m2 (k2+~)2a 2

I 012o

At the longwave limit (k ~ u) all three items indicated depend on k as k2. Providing the inequality (20) is fulflled the sum of these three terms diminishes with rise in k. (This decrease means that the contribution of the translational energy of the ions to the free energy of the system is the most substantial of all the contributions indicated depending on k.) Therefore, the gain in the energy of the interaction of the units on layering (-2XI ~0l 2) may be insufficient for layering into macrophases (k = 0) but sugficient for microphase separation k > 0 ) ; this is connected with decrease in the translational entropy of the counter-ions with increase in k. As for the microphase separated structures proper which may result from the corresponding spinodal breakdown their properties in the equilibrium state require separate investigation. During the development of spinodal breakdown both the formation of one of the classical microphasic structures may occur (lamellar, cylindrical, spherical [12]) and union of the generated microinclusions of one phase into the corresponding macrophase. The fact that at least in a certain region of values of the parameters the final state of the system after spinodal breakdown is microphasically separated may be seen from Fig. lc: for u = 0.125 part of the curve Xc,(¢p) lies at X values less than the value corresponding to the critical point of separation into macrophases. Consequently, this part at any rate lies outside the binodal of macrophase separation. Even where the equilibrium state corresponds to separation into two macroscopic homogeneous phases the microphasic structure appearing in the course of spinodal breakdown may be fixed (on vitrification of the system or on rapid crosslinking of the polymer chains).

Translated by A. CRozY REFERENCES 1. V. V. VASILEVSKAYA, S. G. STARODUBTSEV and A. R. KI-IOIOILOV, Vysokomol. soyed. B29: 390, 1987 (not translated in Polymer Sci. U.S.S.R.). 2. V. Yu. BORYU and I. Ya. YERUKI-IIMOVICH, Dokl. Akad. Nauk S.S.S.R. 286: 1373, 1986. 3. P. DE GENNES, Idei skeilinga v fizike polimerov (Scaling Ideas in Polymer Physics) Moscow, 1982. 4. I. M. LIFSHITS, A. Yu. GROSBYERG and A. R. KHOKI-ILOV, Usp. fiz. nauk. 127: 353, 1979. 5. T. ODIJK, J. Polymer Sci. 15: 477, 1977. 6. I. A. NYRKOVA, Author's Abstr. Dissert. Cand. Phys. Math. Sci. (in Russian) Moscow State Univ., Moscow, 1983. 7. L. D. LANDAU and Ye. M. LIFSHITS, Statisticheskaya fizika (Statistical Physics) Part 1, Moscow, 1976. 8. V. V. VASILIVSKAYA and A. R. KI-IOKI-ILOV,Matematicheskiye metody dlya issledovaniya polimerov (Mathematical Methods of Polymer Investigations) p. 45, Pushchino, 1982.

Spherical micelles of alkylammonium halides

861

9. J. M. DEUTSCH and N. D. GOLDENFELD, J. Phys. 43: 651, 1982. 10. A. S T R O O B A N T S , H. N. W. L E K K E R K E R K E R and T. O D I J K , M a c r o m o l e c u l e s 19: 2232, 1986. 11. I. Ya. Y E R U K H I M O V I C H , Vysokomol. soyed. A24: 1942, 1982 (translated in P o l y m e r Sci. U . S . S . R . 24: 9, 2223, 1982). 12. A. N. S E M E N O V , Zh. eksp. teoret, fiz. 88: 1242, 1985.

PolymerScience U.S.S.R. Vol. 32, No. 5, pp. 861-866, 1990 Printed in Great Britain.

0032-3950/90 $10.00 + .00 © 1991 Pergamon Press plc

RADICAL POLYMERIZATION IN SPHERICAL MICELLES OF UNSATURATED ALKYLAMMONIUM HALIDES IN WATER* V. V. YEGOROV, YE. V. BATRAKOVA and V. P. ZuBov Lomonosov State University, Moscow

(Received 18 January 1989) The kinetics of radical polymerization of N,N-dimethyI-N-alkylacetyl-methacryloylethylammonium halides and their miceilar solutions in water have been investigated. Increase in the polymerization rate was observed in the monomer micelles as compared with their true solutions in ethanol. This is mainly related to the high concentration of the monomer in the micelle as compared with solution. The polymerization rate was found to rise in the spherical micelles of the monomer with increase in the length of the aliphatic suhstituent and decrease in the size of the counter-ion in its molecule. The effective values of the chain propagation kp and bimolecular termination k, rate constants in the micelles have been determined. Constancy of kp and fall in k, were found with increase in the length of the aliphatic substituent and/or reduction in the size of the counter-ion in the monomer molecule while in solution the latter leads to rise in k,. This difference is connected with the different nature of the effects leading to braking of the mobility of the growth radicals in the systems indicated.

IT IS SHOWNin ref. [1] that association of monomer molecules may profoundly affect the kinetics of their radical polymerization in solution. It may be supposed that the kinetics of polymerization are sensitive not only to the formation of the monomer associates but also to change in their structure. It is known that the structure of the associates [2] (micelles) significantly depends on the structure of the compounds forming them. In this connection the aim of the present work is to study the influence of the structure of the molecule of the surfactant monomer (SAM), in particular, the length of the aliphatic substituent and the size of the counter-ion in its molecule on the structure of the associates (micelles) formed by it in water and the kinetics of radical polymerization in them as illustrated by the compounds CH~---C(CH3)COOC2H41~ (CH3)ECH2COOR X - [R = CsHt7 (MA8, X ) ] , CloH21 (MA-10, X), C12H25 (MA-12, X); X = Cl (MA-R, Cl), Br (MA-R, Br). The kinetics of radical polymerization of the monomers in water and ethanol initiated by thermoand photo-breakdown of azoisobutyronitrile respectively at 343 and 308 K (293 K for ethanol) were investigated by the dilatometric method with graduation based on the gravimetric data. The rate of * Vysokomol. soyed. A32: No. 5,927-932, 1990.