Supplementary Information Chain Length Dependence of Polyion

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Supplementary Information

Chain Length Dependence of Polyion Complex Architecture Bearing

Phosphobetaine Block Explored with SAXS and FFF/MALS

Shunsuke Sakamoto 1,2 , Yusuke Sanada 1,2 , Mizuha Sakashita 1,2 , Koichi Nishina 1 , Keita Nakai 3 ,

Shin-ichi Yusa 3 and Kazuo Sakurai* 1,2

1 Department of Chemistry and Biochemistry, The University of Kitakyushu,

1-1 Hibikino, Kitakyushu, Fukuoka 808-0135, Japan.

2 Structural Materials Science Laboratory SPring-8 Center, RIKEN Harima Institute Research,

1-1-1 Kouto, Sayo, Sayo, Hyogo 679-5148, Japan.

3 Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo,

2167 Shosha, Himeji, Hyogo 671-2280, Japan.

* Corresponding author: Kazuo Sakurai

E-mail address: sakurai@kitakyu-u.ac.jp (KS)

Contents

I. Fitting Models of SAXS

II. Hydrodynamic radius and TEM image of PICs

I. Fitting Models of SAXS

According to Pedersen et al 1,2 , the form factor form micelles consisting of spherical core and Gaussian corona chains can be expressed by use of four terms: the self-correlation of the core: , the self-correlation of the corona chains: , the cross term between the core and the corona chains: , and the cross term between different corona chains: S .

F q  N agg

2  2

C

F q  N agg

 2 F q N agg

C

 S q  N agg

( N agg

 1)

 2 S q

(s1)

Here q is the magnitude of the scattering vector, N agg

is the aggregation number, 

C and 

Ch

are the excess scattering lengths of core and corona blocks, respectively. For polymeric micelles, the first term in eq s1 may be regarded as that of homogeneous sphere with radius R

C

:

F q R

C

( ,

C

 A q R s C

)] 2  

3 sin qR  qR cos qR

C C C

( qR

C

) 3

2

(s2)

Here, represents the scattering amplitude of a solid sphere with the radius of R and we assumed that the thickness of the interface between the core and corona region is negligibly small. The second term in eq s1 is the self-correlation of the corona chains, which can be expressed by a Debye function with a radius of gyration ( R g, pMPC

) for the individual corona chain; in the present case the pMPC chain.

F

Ch g, pMPC

)

2

[exp(  q 2 R 2

( q R g, pMPC

) 4 q 2 R 2 ]

(s3)

To eliminate complication and decrease the number of adjustable parameters, we assume that the corona chain density is a constant regardless of the distance from the interface. On this assumption, eq s1 can be rewritten with the corona size of :

 N agg

2

C

A q R

C

)

 

Ch

A q R

Ch

) 

2  N

2 agg Ch Ch

, R g

)

 N

2 agg Ch s

( ,

Ch

)

(s4)

The first term in eq s4 coincides with the scattering intensity from a double layered sphere with and .

In the present case, the first term contributed dominantly at the low q (ca., 0.3 < q ), while the second one became more substantial in the high q in the case of q > 1.0, because the first one decays as while the second one decays as at highq .

3

In the similar manner, the scattering form factor for a mono-layered vesicle consisting of a solid plate and

Gaussian corona chains attached to the plate surface can be expressed by the equation of four-layered spheres with the innermost layer being the same electron density with the solvent:

) 

 i

4 

 1

 i i  1

V A s

( q , R i

)

2

 N agg

 2 F ( q ) (s5)

Where R

2

 R

1

 R

4

 R

3

, which is the thickness of the inner and outer layer of pMPC, ρ i

is the electron density of the i th layer, ρ solv

is the electron density of the solvent and 

1

  

5 solv

,  

1 2

 

4

 

5 due to the same chemical component of pMPC, and N agg

β 2 Ch was given from the total number of the electron of the shell

chains and the aggregation number N agg

β 2 Ch

= ( N agg

β

Ch

) 2 / N agg

= [( ρ

3

– ρ

2

)( V

2

– V

1

) + ( ρ

5

– ρ

4

)( V

4

– V

3

)] 2 / N agg

.

When N agg

> 30, the third term in eq s4 became negligibly small; therefore, we omitted this term in eq s5.

For the case of cylinders with a finite length of L , we used the following equation similar with eq s5, assuming Gaussian chains attaching on the cylinder surface with the radius of R g , pMPC

.

/2

0

N agg

2

  

1 2

 cy

( ,

1

 

 

2 solv

 cy

( ,

2

2

   N agg

 2 F q

(s6)

  j qL 

(

 qR sin

Here, ρ

1

and ρ

2

is the electron densities of the core and shell regions, V

1

and V

2

is the volume of the core and shell cylinders given by V i

= π R i

2 L , N agg

β 2 Ch

was calculated from the same manner of vesicle N agg

β 2 Ch

=

( N agg

β

Ch

) 2 / N agg

= [( ρ

2

– ρ sol

)( V

2

– V

1

)] 2 / N agg

, j and

0

J are the zero-th order of the spherical Bessel function

1 and the 1 st order of the Bessel function, respectively.

II. Hydrodynamic radius and TEM image of PICs

Figure S1. (a) Hydrodynamic radius ( R h

) and (b) scattering intensity for the PIC micelles with f + = 0.5 at C p

= 1.0 g/L in 0.1 M NaCl aqueous solutions at 25 °C as a function of sodium chloride concentration ([NaCl]):

P

100

M

96

/P

100

A

99

(C10, ○), P

100

M

48

/P

100

A

45

(C05, ▲), and P

100

M

27

/P

100

A

27

(C03, ◊).

3

Figure S2. Transmission Electron Microscopy (TEM) for C50 and observed short worm-like cylinders

Reference

1 Choi, S.-H., Bates, F. S. & Lodge, T. P. Structure of Poly(styrene-b-ethylene-alt-propylene) Diblock

Copolymer Micelles in Squalane†. The Journal of Physical Chemistry B 113, 13840-13848, doi:10.1021/jp8111149 (2009).

2 Pedersen, J. S., Svaneborg, C., Almdal, K., Hamley, I. W. & Young, R. N. A Small-Angle Neutron and X-ray

Contrast Variation Scattering Study of the Structure of Block Copolymer Micelles:   Corona Shape and

Excluded Volume Interactions. Macromolecules 36, 416-433, doi:10.1021/ma0204913 (2003).

Roe, R. J. Methods of X-ray and Neutron Scattering in Polymer Science . (2000).

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