Ordered Fluids and Liquid Crystals

ture in such ternary systems has so far disclosed five main types of phase diagram. ..... 23 tion(130°C.). Cooling to. 20° in air by agitation (ca. ...
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9 Occurrence of Different Mesomorphous Phases in Ternary Systems of Amphiphilic Substances and Water

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L E O M A N D E L L , K R I S T E R F O N T E L L , and

PER

EKWALL

Laboratory for Surface Chemistry, Royal Swedish Academy of Engineering Sciences, Stockholm, Sweden

A thorough study has been made of the system sodium caprylate­ -decanol-water at 20°C. Various mesophases in the heterogene­ ous regions can be separated by centrifugation under suitable conditions. The mesomorphous substance has different in­ ternal structures in different concentration regions, and these structures do not change continuously into one another but repre­ sent separate mesophases. The regions of existence of the various mesophases are separated by two- and three-phase regions, where two or three phases occur side by side in accordance with the re­ quirements of the phase rule. Similar conditions have been shown in a large number of other ternary systems. A systematic study of the dependence of phase equilibrium on molecular struc­ ture in such ternary systems has so far disclosed five main types of phase diagram.

J η a d d i t i o n to t h e order o n t h e m o l e c u l a r l e v e l , w h i c h is c h a r a c t e r i s t i c of systems w i t h t h e r m o t r o p i c m e s o m o r p h i s m , t h e l y o t r o p i c mesomorphous systems are also distinguished b y the arrangement of aggregates i n a s u p e r l a t t i c e . T h e s e systems e x h i b i t n o t o n l y t h e j o i n i n g a n d d i r e c t i n g forces between i n d i v i d u a l molecules b u t also t h e i n t e r a c t i o n between larger m o l e c ­ u l a r aggregates—for instance, m i c e l l e - l i k e aggregates—and a c c o u n t m u s t be t a k e n of t h e i r i n t e r n a l a r r a n g e m e n t . T h i s w o u l d appear to e x p l a i n t h e v a r i e t y of t h e i n n e r s t r u c t u r e of t h e l y o t r o p i c mesomorphous systems. L i q u i d c r y s t a l l i n e p r o d u c t s are f o r m e d i n aqueous soap systems at h i g h concentrations. T h e existence of different mesophases i n s u c h systems w a s observed b y M c B a i n (17, 18). T o w a r d t h e end of t h e 1950's L u z z a t i et al. (11,14,15,16) discovered b y x - r a y d i f f r a c t i o n v a r i o u s m e s o m o r p h o u s s t r u c ­ tures i n these t w o - c o m p o n e n t systems a n d regarded this as a proof t h a t t h e y c o n t a i n e d different mesophases, w h i c h , however, t h e y d i d n o t separate, 89 Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

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90

ORDERED FLUIDS A N D LIQUID CRYSTALS

T h e presence i n systems of soap a n d s o a p l i k e substances of a t h i r d c o m p o n e n t w i t h a m p h i p h i l i c a n d p r e d o m i n a n t l y l i p o p h i l i c properties s t r o n g l y promotes t h e f o r m a t i o n of aqueous m e s o m o r p h o u s phases. I n s u c h t e r n a r y systems a n extensive, c o n t i n u o u s c o n c e n t r a t i o n region c o n ­ t a i n i n g mesomorphous substances often forms, f r o m f a i r l y l o w c o n c e n t r a ­ tions u p w a r d . T h e v i e w c o m m o n l y h e l d d u r i n g t h e 1950's a n d l a t e r t h a t there is o n l y one mesomorphous phase i n t h i s region (1, 2, 3, 12, 13, 22) w o u l d seem to be i n c o r r e c t ; o u r x - r a y d i f f r a c t i o n studies h a v e disclosed t h a t the region contains areas of different i n n e r s t r u c t u r e of t h e m e s o m o r p h o u s m a t t e r a n d t h a t d i s t i n c t m e s o m o r p h o u s phases, each w i t h i t s o w n i n n e r s t r u c t u r e , properties, a n d area of existence, c a n be separated b y c e n t r i f u g a t i o n . B e t w e e n these areas are t w o - a n d three-phase regions, where, i n c o n ­ f o r m i t y w i t h t h e phase rule, t h e phases occur side b y side (J+-8, 10, 19, 20, 21). Previous Investigations of Sodium Decanol-Water System

Caprylate-

W e first consider a m o d e l s y s t e m of s o d i u m c a p r y l a t e , decanol, a n d water. I n F i g u r e 1 a l l t h e c o n c e n t r a t i o n areas i n w h i c h a n y mesomorphous substance at a l l has been observed are i n c l u d e d i n one extensive region r e ­ ferred t o as ' ' l i q u i d c r y s t a l / ' R e g i o n s L\ a n d L consist of homogeneous, 2

Decanol

Water

Na-caprylate

Figure 1.

Triangular diagram of three-component system sodium caprylate-decanol-water at 20°C.

L\. Homogeneous, isotropic solutions in water L. Homogeneous, isotropic solutions in decanol L\ + J'2· Two-phase region consisting of L\ and L2 Liquid crystal" area comprises all regions where mesomorphous matter exists. Areas denoted by - f contain mesomorphous matter and homogeneous isotropic solutions in equilibrium 2

u

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

9.

MANDELL ET AL.

Mesomorphous

91

Phases

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Decanol

Water Figure 2.

Na-caprylate Triangular diagram of three-component system sodium caprylate-decanol-water at 20°C.

L\. Homogeneous, isotropic solutions in water L. Homogeneous, isotropic solutions in decanol L\ + L . Two-phase region consisting of L\ and L Li + L.C. Two-phase region consisting of L\ and mesomorphous matter L + L.C. Two-phase region consisting of L and mesomorphous matter Liquid crystal area comprises all regions where only mesomorphous matter exists. 2

2

2

2

2

i s o t r o p i c s o l u t i o n s ; i n L i w a t e r is t h e solvent, i n L , decanol. 2

L\ extends t o

t h e w a t e r corner (as a n a r r o w region close t o t h e base l i n e , j u s t discernable o n t h e scale of t h e figure.).

T h e region L\ + L

two-phase region where solutions L\ a n d L

2

2

o n t h e extreme left is a

are i n e q u i l i b r i u m .

Within

t h e large l i q u i d c r y s t a l region there are areas w i t h a n i s o t r o p i c s o l u t i o n L\ o r L , as w e l l as t h e m e s o m o r p h o u s 2

i n d i c a t e d b y a p l u s sign.

matter.

T h e sites of s u c h areas are

I n some cases t h e s o l u t i o n w i l l u l t i m a t e l y sep­

arate m o r e o r less c o m p l e t e l y f r o m t h e m e s o m o r p h o u s s u b s t a n c e ; s e p a r a t i o n c a n be effected b y c e n t r i f u g a t i o n . taining solution a n d mesomorphous F i g u r e 2 is o b t a i n e d .

complete

W h e n these regions

con­

m a t t e r are m a r k e d i n t h e d i a g r a m ,

H e r e , t h e l i q u i d c r y s t a l area c o n t a i n s o n l y c o n c e n ­

t r a t i o n regions where there is m e s o m o r p h o u s substance b u t n o solutions. X - r a y d i f f r a c t i o n has s h o w n t h a t t h e i n n e r s t r u c t u r e of t h e m e s o ­ m o r p h o u s m a t t e r v a r i e s f r o m one p a r t of t h e l i q u i d c r y s t a l area t o a n o t h e r (5, 6, 10).

T h e o v e r - a l l p i c t u r e of t h e x - r a y d i f f r a c t i o n p i n h o l e p a t t e r n s

p r o v i d e d b y t h e substance i n t h i s area is t h e f o l l o w i n g (10) : a l l t h e p a t t e r n s show a diffuse, w e a k , w a t e r reflection w i t h a v a l u e of 1/3.2 A . a n o t h e r reflection w i t h a v a l u e of 1/4.5 A . flection

- 1

.

-

1

for S a n d

T h e fact t h a t t h e l a t t e r r e ­

is i d e n t i c a l i n p o s i t i o n a n d shape t o t h a t for l i q u i d paraffin c h a i n

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

92

ORDERED FLUIDS A N D LIQUID CRYSTALS

h y d r o c a r b o n s indicates t h a t t h e paraffin chains of t h e a m p h i p h i l i c c o m ­ p o u n d s i n t h e mesomorphous substance are i n a m o r e o r less l i q u i d state. I n a d d i t i o n t o these reflections there is i n t h e " l o w a n g l e " r e g i o n — t h a t i s , at angles below 10°—a series of s h a r p lines, w h i c h are as d i s t i n c t as i f t h e y were g i v e n b y a t r u l y c r y s t a l l i n e substance.

T h e s e l o w angle p a t t e r n s ,

however, differ f r o m one p a r t of t h e l i q u i d c r y s t a l region t o another. A r o u n d position ·

x - r a y d i f f r a c t i o n p a t t e r n s designated as t y p e Ε are

o b t a i n e d (10) ( F i g u r e 3 ) .

A n a l y s i s of t h e p h o t o g r a m s gives t h e r a t i o b e ­

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tween t h e B r a g g spacings as 1:

1 / V 3 : 1/ V~4—that i s , t h e y satisfy t h e

Figure 8. Low-angle x-ray diffraction pat­ terns of a mesomorphous substance with type Ε hexagonal structure Bragg spacing ratio 1:1/

V8:l/\/4

c r i t e r i o n f o r a t w o - d i m e n s i o n a l h e x a g o n a l arrangement. T h e d i f f r a c t i o n d i a g r a m has a s p o t t y appearance even w h e n t h e s a m p l e is r o t a t e d . T h e spots are often arranged i n a definite h e x a g o n a l p a t t e r n , a n d occasionally p h o t o g r a m s were o b t a i n e d w i t h three concentric six-rings w i t h a r e l a t i v e displacement of 30°. T h i s suggests a s y s t e m of h e x a g o n a l l y a r r a n g e d p a r a l l e l c y l i n d e r s . T h e c y l i n d e r s themselves are composed of a m p h i p h i l i c m a t t e r — c a p r y l a t e a n d d e c a n o l — a n d t h e i r core consists of h y d r o c a r b o n chains i n a l i q u i d o r s e m i l i q u i d s t a t e ; t h e h y d r o p h i l i c e n d groups are anchored t o t h e surface of t h e c y l i n d e r s a n d are i n contact w i t h t h e w a t e r s e p a r a t i n g t h e c y l i n d e r s . T h e u n i t cell p a r a m e t e r of t h i s hexagonal n e t ­ w o r k is 30 t o 35 A . T h e same t y p e of x - r a y d i f f r a c t i o n p a t t e r n is o b t a i n e d i n t h e p a r t s of the s y s t e m a r o u n d p o s i t i o n | (10) ( F i g u r e 4 ) ; t h i s indicates t h a t here, too, is a s i m i l a r t w o - d i m e n s i o n a l h e x a g o n a l arrangement. T h e u n i t cell p a r a m e t e r for t h e h e x a g o n a l n e t w o r k , however, is u p t o 47 Α . , a v a l u e t h a t is inconsistent w i t h t h e above m o d e l since t h e p r o p o r t i o n of w a t e r is too l o w i n r e l a t i o n t o t h e a m o u n t of a m p h i p h i l i c substance. I t is therefore neces­ s a r y t o assume w h a t m a y be referred t o as a n inverse h e x a g o n a l s t r u c t u r e ,

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

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9.

MANDELL ET AL.

Mesomorphous

93

Phases

Figure 4- Low-angle x-ray diffraction pat­ tern of a mesomor­ phous substance with type F hexagonal structure Bragg spacing ratio

1:1/V8:1/V4 w i t h l o n g p a r a l l e l w a t e r c y l i n d e r s i n h e x a g o n a l a r r a n g e m e n t , separated b y a l i q u i d or s e m i l i q u i d h y d r o c a r b o n e n v i r o n m e n t consisting of molecules of the a m p h i p h i l e s w i t h t h e h y d r o p h i l i c groups f a c i n g the water. W e c a l l this s t r u c t u r e t y p e F . I n the m i d d l e of t h e s y s t e m , a r o u n d p o i n t s X i n F i g u r e 2, a m e s o ­ m o r p h i c s t r u c t u r e was encountered t h a t gave x - r a y d i f f r a c t i o n p a t t e r n s of a c o m p l e t e l y different k i n d (10) ( F i g u r e 5). T h e s e show u p t o three d i s ­ t i n c t reflections, whose B r a g g spacings are i n the r a t i o 1 : 1 / 2 : 1 / 3 . Here, t h e n , is a n arrangement w i t h l i n e a r s y m m e t r y consisting of layers of a m ­ p h i p h i l i c substance a l t e r n a t i n g w i t h layers of w a t e r molecules. T h e for­ m e r are o b v i o u s l y c o m p o s e d of double layers of a m p h i p h i l i c molecules, arranged w i t h the h y d r o p h i l i c groups facing o u t w a r d t o w a r d t h e w a t e r a n d

Figure 5. Low-angle x-ray diffraction patterns of mesomorphous substances with lamellar structures types D (left) and C (right) Bragg spacing ratio 1: Λ: Α λ

λ

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

O R D E R E D FLUIDS A N D LIQUID CRYSTALS «20 A

r

100

80 9

Phase Β Phase D

y

60 40 10

20

30

50

40

moles of H 0

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2

molts of (No Cy + Decanol) 100 A

80

Phase Β

60

40 10

20 moles of H 0

30

40

2

moles of (N a Cy4-Decanol) 45 A Phase C

401-

35 PhaseD 30

8 10 12 moles of H 0

14

16

2

moles of (N a C y 4-Decanol) Figure 6. Dependence of Bragg spacing on water content of meso­ morphous substance, sodium caprylate-decanol-water, at 20°C. Upper. Center. Lower.

Transition from mesophase D to mesophase B. Molar ratio for decanol-sodium caprylate. Meso­ phase D = 2.4, mesophase Β = 1.4 to 1.9 Transition from mesophase C to mesophase B. Molar ratio for decanol-sodium caprylate X 1.56 Transition from mesophase D to mesophase C. Molar ratio for decanol-sodium caprylate X 1.56

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

9.

MANDELL ET AL.

Mesomorphous

Phases

95

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the m o r e or less p a r a l l e l h y d r o c a r b o n chains i n w a r d , f o r m i n g a l i q u i d o r semiliquid hydrocarbon region w i t h i n the double layer. W e have, h o w ­ ever, f o u n d three d i s t i n c t s u b t y p e s w i t h l i n e a r s y m m e t r y , w h i c h differ i n t h a t t h e i r B r a g g spacings v a r y d i f f e r e n t l y w i t h t h e w a t e r content of the mesomorphous substance ( F i g u r e 6) (5). T h e s e w e c a l l t y p e s D , C., a n d B . T h e m o s t extensive is t y p e D . I f a l l t h e mesomorphous m a t t e r of t h e l i q u i d c r y s t a l area belonged to one phase, there w o u l d be a c o n t i n u o u s change of t h e different i n n e r s t r u c ­ tures i n t o another. H o w e v e r , t h i s was n o t t h e case, for each s t r u c t u r e represents a d i s t i n c t phase, a n d t h e areas c o n t a i n i n g homogeneous m e s o ­ phases are separated f r o m one a n o t h e r b y t w o - a n d three-phase zones, w i t h i n w h i c h the t w o or three phases, r e s p e c t i v e l y , exist i n e q u i l i b r i u m (4, 5, 0, 10). Is There a True Equilibrium

State?

T o e x a m i n e t h e phase e q u i l i b r i a i n t h e s y s t e m m e n t i o n e d , m i x t u r e s of s o d i u m c a p r y l a t e , d e c a n o l , a n d w a t e r were p r e p a r e d i n different w a y s . T h e t i m e to r e a c h e q u i l i b r i u m was shortened b y m i x i n g , v i g o r o u s s h a k i n g , a n d p r o l o n g e d w a r m i n g . I n some experiments finely p o w d e r e d s o d i u m c a p r y l a t e a n d d e c a n o l were m i x e d t h o r o u g h l y a n d a l l o w e d to s t a n d at v a r i ­ ous t e m p e r a t u r e s before w a t e r was a d d e d , e i t h e r i n s m a l l p o r t i o n s at d i f f e r ­ ent i n t e r v a l s or a l l at once. T h e m i x t u r e was s u b s e q u e n t l y t r e a t e d at d i f ­ ferent t e m p e r a t u r e s . I n o t h e r experiments s o d i u m c a p r y l a t e a n d w a t e r were m i x e d a n d h e a t e d u n t i l a homogeneous s o l u t i o n was o b t a i n e d or u n t i l there w a s no f u r t h e r c h a n g e ; d e c a n o l w a s t h e n a d d e d , e i t h e r i n s m a l l p o r ­ tions at different i n t e r v a l s or as a single v o l u m e . I n t h e o t h e r e x p e r i m e n t s a l l three components were m i x e d , a n d the r e a c t i o n was p r o m o t e d b y t h o r ­ o u g h m i x i n g a n d a g i t a t i o n for different periods a n d at a range of f a i r l y h i g h t e m p e r a t u r e s (100° to 1 8 0 ° C ) . A l l the m i x t u r e s were m i x e d i n glass a m p o u l e s , w h i c h were t h e n sealed. I r r e s p e c t i v e of t h e m e t h o d of t r e a t ­ m e n t , a l l t h e samples were cooled to r o o m t e m p e r a t u r e w i t h c o n s t a n t a g i t a ­ t i o n . T h e p e r i o d of storage was never less t h a n 24 h o u r s , even i f e q u i l i b ­ r i u m h a d been o b t a i n e d i n a shorter t i m e , a n d some were stored for as l o n g as 13 weeks. W h a t e v e r t h e m e t h o d of p r e p a r a t i o n , t h e state of e q u i l i b r i u m o b t a i n e d for each m i x t u r e was a l w a y s t h e same (5, 6). T h a t t h e systems were i n t r u e e q u i l i b r i u m is e v i d e n t f r o m t h e findings g i v e n i n the f o l l o w i n g tables for samples w i t h t h e same c o m p o s i t i o n b u t different t r e a t m e n t . I r r e s p e c t i v e of t h e m e t h o d of t r e a t m e n t , samples h a v i n g t h e same c o m p o s i t i o n gave t h e same x - r a y d i f f r a c t i o n p a t t e r n s w i t h the same B r a g g s p a c i n g . T h e y also d i s p l a y e d the same m i c r o s c o p i c t e x t u r e a n d o t h e r ex­ t e r n a l properties. I n the examples presented i n T a b l e I c e n t r i f u g a t i o n d i d n o t result i n s e p a r a t i o n i n t o l a y e r s , n o r d i d i t disclose a n y difference i n x - r a y p a t t e r n or e x t e r n a l p r o p e r t i e s ; w e therefore concluded t h a t t h e samples were homogeneous f r o m t h e s t a n d p o i n t of phase. A l l the p r e p a r a t i o n s i n T a b l e s I I a n d I I I separated i n t w o l a y e r s , w h i c h differed i n c o m p o s i t i o n , x - r a y d i f f r a c t i o n p a t t e r n , a n d m i c r o s c o p i c t e x t u r e .

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

96

O R D E R E D

F L U I D S

A N D

L I Q U I D

Table I.

C R Y S T A L S

Samples from Storage

Initial Composition, % Sample

NaCy

E l

41.0

^l^n^

H0

Dec.

48.0

11.0

2

Treatment

Days

Heating to homogeneous solution(130°C.). Cooling to

23

20° in air by agitation (ca. 5°/ i ) Heating to homogeneous solution(130°). Cooling in stages to 20° over 5 days Heating to homogeneous solution(130°). Rapid cooling in ice bath. Warming in stages to 20°, over 5 days

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m

E2

41.0

48.0

11.0

Ε 3

41.0

48.0

11.0

D 1

30.0

31.0

39.0

D 2

30.0

31.0

39.0

D3

30.0

31.0

39.0

n u t e

81

22

Heating to homogeneous solution(130°). Cooling to 20° in air by agitation (ca. 5 ° / minute) Heating to homogeneous solution(130°). Cooling i n stages to 20°, over 5 days Heating to homogeneous solution (130°). Rapid cooling in ice bath. Warming in stages to 20°, over 5 days

21

81

22

Table II. Preparations Samples w i t h the Same C o m p o s i t i o n Centrifuge

Data

Top

Approximate Storage Initial Composition, Sample I

E

2

b

3

C

4

d

5

e

NaCy

Distribution

Time %

„,

m

o

fry r

Days

Layer

%

W

4

p

M

g

T

i

m

e

^

fyO

Dec.

hrs.

3 9 . 5

3 9 . 5

2 1 . 0

9

100,000

17

3 9 . 5

3 9 . 5

2 1 . 0

7

100,000

39.5

3 9 . 5

2 1 . 0

30

3 9 . 5

3 9 . 5

2 1 . 0

39.5

3 9 . 5

2 1 . 0

Volume N

o

o

f

layers

T

o

p

B

o

t

t

o

m

Composition, NaCy

Ηφ

layer

2

5 8 . 0

4 2 . 0

3 9 . 0

3 2 . 9

2 8 . 1

16

2

5 7 . 0

4 3 . 0

3 8 . 8

3 2 . 8

28.4

100,000

15

2

5G.0

4 4 . 0

3 8 . 8

32.9

2 8 . 3

G

100,000

10

2

5 0 . 0

4 4 . 0

38.9

3 3 . 0

2 8 . 1

0

100,000

10

2

5 0 . 0

4 4 . 0

3 9 . 0

33.1

27.9

Treatment a

b

c

Heating

to

100°C.

%

layer

N o n h o m o g e -

neous solution. Cooling in air b y agitation (ca. 5 ° / m i n u t e ) Heating to homogeneous solution (ca. 160°). Cooling to 20° in air b y agitation (ca. 5 ° / m n i u t e ) A s preparation 2

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

Dee.

9.

M A N D E L L

Mesomorphous

E TA L .

97

Phases

One-Phase Regions X-Ray Diffraction Data

Downloaded by RUTGERS UNIV on December 28, 2017 | http://pubs.acs.org Publication Date: January 1, 1967 | doi: 10.1021/ba-1967-0063.ch009

Bragg spacing, Α.

Structure

Centrifuge Data

Micro­ scopic Texture

Field, g

Time, hr.

32.0, 18.4, 15.9

Hexagonal type Ε

Type Ε

130,000

3

31.5,18.2,15.8

Hexagonal type Ε

Type Ε

130,000

4

31.6, 18.5, 15.9

Hexagonal type Ε

Type Ε

130,000

3

31.8, 16.0, 10.6

Linear type D

Type D

130,000

5

31.8,

16.0

Linear type D

Type D

130,000

4

32.2,

16.0

Linear typeD

Type D

130,000

6

Resuit

No separation. No change in properties

No separation. N o change in properties

from a Two-Phase Region but Different Treatment, Ε + Top

X-Ray

Micro­

Bottom

Diffraction

texture

spacing, A.

Structure

Micro-

Data

Bragg

scopic

D

Layer

Composition, NaCy

%

X-Ray

Diffraction

scopic

H0

Dec.

texture

2

Layer

Type D

Linear, type D

40.7

48.0

11.3

Type Ε

Hexagonal, type Ε

Type D

Linear, type D

40.7

48.1

11.2

Type Ε

Hexagonal, type Ε

Type D

Linear, type D

40.6

48.2

11.2

Type Ε

Hexagonal, type Ε

Type D

Linear, type D

40.6

48.2

11.2

Type Ε

Hexagonal, type Ε

Type D

Linear, type D

40.8

48.4

10.8

Type Ε

Hexagonal, type Ε

d

e

30.2,

15.0

Data

Bragg Structure

spacing, A.

I 32.0, 18.3, I 16.0

H e a t i n g to homogeneous solution (ca. 1 6 0 ° ) . R a p i d cooling i n ice bath. W a r m i n g i n stages to 2 0 ° over 3 d a y s H e a t i n g to homogeneous solution (160°). C o o l i n g i n stages to 2 0 ° over 5 d a y s

Porter and Johnson; Ordered Fluids and Liquid Crystals Advances in Chemistry; American Chemical Society: Washington, DC, 1967.

98

ORDERED

FLUIDS A N D LIQUID

CRYSTALS

Table III. Preparations Samples w i t h Same Composition Centrifuge

Data

Top

Approximate Storage Initial

Downloaded by RUTGERS UNIV on December 28, 2017 | http://pubs.acs.org Publication Date: January 1, 1967 | doi: 10.1021/ba-1967-0063.ch009

Sample

NaCy

Distribution 6?/

Volume

~To~p

Bottom

Time %

Composition,

t20°C.,

a

Days

Layer

%

Field,

Time,

g

No.

hr.

of

layers

Composition, NaCy

H2O

%

H2O'

Dec.

layer

layer

I

e

21.0

25.0

54.0

10

20,000

17

2

49

51

17.3

20.4

62.3

Dec.

2

6

21.0

25.0

54.0

30

20,000

19

2

50

50

17.3

20.2

62.5

3

C

21.0

25.0

54.0

40

20,000

16

2

52

48

17.3

20.4

62.3

4*

21.0

25.0

54.0

6

20,000

17

2

51

49

17.4

20.1

62.5



21.0

25.0

54.0

6

20,000

17

2

51

49

17.4

20.2

62.4

6/

21.0

25.0

54.0

3

20,000

16

2

51

49

17.3

20.4

62.3

Treatment a

b c

H e a t i n g to homogeneous solution. C o o l i n g to 2 0 ° C . i n a i r b y a g i t a t i o n (ca. 5 ° / m i n u t e ) A s i n preparation 1 A s i n preparation 1

Table IV.

Preparation

Samples w i t h the Same Composition Top

Initial Composition, Sample

l

a

NaCy

^Time %

H2O

Dec.

36.0

47.2

16.8

at20°C.,

Centrifuge

Data

Micro-

Field

Time,

g

hr.

5

100,000

17

3

Days

Layer

No. layers

of

Composition, NaCy

%

scopic

H2O

Dec.

texture

36.2

34.3

29.5

Type D

2

b

36.0

47.2

16.8

28

70,000

16

3

36.4

33.5

30.1

Type D

3

C

36.0

47.2

16.8

6

100,000

16

3

36.1

34.2

29.7

Type D

47.2

16.8

100,000

17

3

36.2

34.3

29.5

Type D

4