Summary of studies looking at polymers confined to nanosized pores. Includes studies in metal-organic frameworks and other porous templates.

1. Polymers in Confinement
David N Bunck
Topical Review
28 November 2012

2. Polymer Size
Hiemenz and Lodge, Polymer Chemistry, 2nd ed.
Milsev, J Phys Condens Matter, 2011, 23, 103101.
de Gennes, Scaling Concepts in Polymer Physics,
Cornell University Press: 1979.
R = aN3 5 Rg ∝ N3 5
(Rg ∝ N0.589
)
a - size of monomeric unit
N - number of units
End-to-End Distance Radius of Gyration

3. Blah Blah Blob
F(R)
kBT
=
R2
aN2 +
ad
N2
Rd
elasticity
excluded
volume
free energy
R
R0
∝ aN
a
D
⎛
⎝
⎜
⎞
⎠
⎟
2 3
τR ∝ a2
N2 a
D
⎛
⎝
⎜
⎞
⎠
⎟
1 3
a - size of monomeric unit
N - number of units
relaxation time
Fconf = TN
a
D
⎛
⎝
⎜
⎞
⎠
⎟
5 3
confinement
energy
Milsev, J Phys Condens Matter, 2011, 23, 103101.
Yeomans et al., Soft Matter, 2012, 8, 4306.
J* - threshold flow rate

4. Confined Polymerization
M2(bdc)2(dabco)2
M = Zn2+ (1a)
M = Cu2+ (1b)
CO2H
CO2H
bdc
N
N
dabco
Endo et al., Chem Commun., 2005, 5968.
0.1 M NaOH1.
2. CHCl3 / MeOH
cycles
PS
1a Mn = 56.2 kDa
PDI = 1.66
Control
PDI = 4.68
AIBN
N
N
CN
CN
AIBN
ESR: 21 d, 70 °C
7.5 x 7.5 Å 8.2 x 6.0 Å

5. Protected Polymerization
Kitagawa et al., ACIE, 2007, 46, 4987.
Mn = 9.3 kDa
Mw = 48.3 kDa
PDI = 5.19
Mn = 5.8 kDa
Mw = 10.9 kDa
PDI = 1.88
Cross-linked
M2(bdc)2(dabco)2
M = Zn2+ (1a)
M = Cu2+ (1b)
CO2H
CO2H
bdc
N
N
dabco
0.9 mols
adsorbed

6. Rollin’ on Dubs
Kitagawa et al., JACS, 2008, 130, 6781.
lnW = lnW0 +
A
βE0
⎛
⎝
⎜
⎞
⎠
⎟
2
M2(bdc)2(dabco)2
M = Zn2+ (1)
CO2H
CO2H
bdc
N
N
ted
10 μm
Dubinin-Radushkevich
Vp = 0.637 cm3
g-1
Vp = 0.292 cm3
g-1
ρ = 0.55 g cm-3
(vs 1.04)
(vs 0.969)?
W0 = saturated N2 pressure
Zirkel et al., Macromolecules, 1994, 27, 4639.

7. 1
H-13
C HETCOR SSNMR
Kitagawa et al., JACS, 2008, 130, 6781.
1 ms
5 ms
Empty Framework
CO2H
CO2H
bdc
N
N
ted
PS Filled

8. Single Chain Dynamics
Kitagawa et al., JACS, 2008, 130, 6781.
PS (Bulk) PS (MOF)
Ph: 180° flip - k1 ~105
s-1
rotation - k2 ~108
s-1
librations - k3 ~1010
s-1
Flipping gives rise to singularities (89 vs 94%)
τc =τc0 exp
Ea
RT
1
T1
∝
1
τc
Ea = 2.10 kcal mol-1

9. Other Monomers
Kitagawa et al., Macromolecules, 2008, 41, 87.
M2(bdc)2(dabco)2
M = Zn2+ (2b)
M = Cu2+ (1b)
CO2H
CO2H
bdc
N
N
dabco
Cu2+
Zn2+
Cu2+
OH
OHO
O
2c 2d
Adsorbed Styrene
10.8 Å
7.5 Å
5.7 Å
4.8 x 4.3 Å

10. Staying Regular
Kitagawa et al., Macromolecules, 2008, 41, 87.
10.8 Å
7.5 Å
5.7 Å
4.8 x 4.3 Å
Ph
Me
CO2Me
ESR: 2.6 mmol kg-1
0.48 mmol kg-1
Soluton FRP: 10-4
- 10-5
mmol kg-1

11. On the Side
Kitagawa et al., ACIE, 2006, 45, 4112.
Mita et al., Nature, 2005, 436, 238.
OMe
O
H
CO2Me
H
12 h, r.t.
conditions
a) MOF, 12 h, r.t.
b) O
ONa
30 d, r.t.
30 d, 70 °C
Mn = 850 Da
Mw = 4800 Da
PDI = 5.65
(PS Standards)
trace
yellow oil

12. PEO’d
Kitagawa et al., Nat Commun, 2010, 1:83.
chain-chain
assemblies
1, 2, 3, 4
O
O
n
PEO

13. Pyrrole the Dice
[(Me3Sn)3FeIII(CN)6]n [(Ppy)(Me3Sn)3FeII(CN)6]n
H
N
Fischer et al., ACIE, 1989, 28, 1263.
Calleja et al., ACIE, 1989, 28, 1265. Kitagawa et al., Chem Mater, 2009, 21, 4096.
SBET
90 m2
g-1
PANI-SBA-15
NH2
SBET (M2 g-1
) H+
(S cm-1
)
SBA-15 739 -
Monomer Soak 461 0.1
Vapor Dif. 443 0.55
In situ 565 1.67
Balkus Jr et al., Micro and Meso Mater, 2005, 81, 321.

14. Poly(styrene) in Alumina
Russell et al, Nat Mater, 2007, 6, 961.
Al2O3 Template: 15 nm x 120 μm
Rg(PS) ~45 nm (591 kDa)
Capillary rise into
the pores
114 → 2880 kDa
Q - integrated intensity
πr2
Δl = −KΔ Q Q0( )
η ∝ N1.5
Predicted
Measured
3.4 x 10-3
Pa s (15 nm)
4.4 x 10-6
Pa s (bulk)

15. Confinement Effects on Rg
Russell et al, Nat Mater, 2007, 6, 961.
Unpreturbed along pore axis

16. Crystal Clear
Mijangos et al., Macromolecules, 2012, 45, 1517.
PEO, 20 nm
O
O
n
PEO
Reduced Tc
E53S47

17. For Take Away
Kitagawa system well studied
Other opportunities for porous templates

18. Further Reading
• MOF
– Kitagawa et al., Chem Soc Rev, 2009, 38, 1228.
– Uemura, Bull Chem Soc Jpn, 2011, 84, 1169.
• Templates
– Anonietti et al., Chem Mater, 2008, 20, 738.
• Encapsulated Conducting Polymers
– Cardin, Adv Mater, 2002, 14, 553.