Copyright WILEY-VCH Verlag GmbH & Co. KGaA, 69469 Weinheim, Germany, 2012.
Supporting Information
for Adv. Funct. Mater., DOI: 10.1002/adfm.201202323
Hierarchical Assembly of Complex Block Copolymer
Nanoparticles into Multicompartment Superstructures through
Tunable Interparticle Associations
Jiahua Zhu, Shiyi Zhang, Fuwu Zhang, Karen L. Wooley,*
and Darrin J. Pochan*
Submitted to
Supporting Information for DOI: 10.1002/adfm.201202323
Hierarchical assembly of complex block copolymer nanoparticles into
multicompartment superstructures through tunable inter-particle associations
Jiahua Zhu1,‡, Shiyi Zhang2,3,‡, Fuwu Zhang2, Karen L. Wooley2*, Darrin J. Pochan1*
1 Department of Materials Science and Engineering, University of Delaware
2 Departments of Chemistry and Chemical Engineering, Texas A&M University
3 Department of Chemistry, Washington University in St. Louis
1. Experimental section
Materials
Poly(acrylic acid)90-b-poly(methyl methacrylate)100 (PAA90-b-PMMA100) diblock
copolymers were synthesized by acidolysis of PtBA90-b-PMMA100 (PDI<1.20) precursors,
which were prepared by sequential polymerization of methyl methacrylate and tert-butyl
acrylate via atom transfer radical polymerization (ATRP).[1] IR: 3100-2900, 1750-1620,
1447, 1270-1080 cm−1. 1H NMR (DMF-d7, ppm): δ 3.92-3.75 (s, -OCH3), 2.76–1.26
(br,-CHCH2- of the polymer backbone), 1.23-0.91 (s, CH3). 13C NMR (DMF-d7, ppm): δ
177.8, 176.4, 54.4-51.7, 44.6-41.5, 36.7-35.5. DSC: (Tg)PMMA = 119.5 °C, (Tg)PAA = 133.5 °C.
TGA in N2: 200–330 °C, 20% mass loss; 330–450 °C, 64% mass loss, 10% mass remaining
above 450 °C.
Poly(18-crown-6-g-acrylic
acid)90-b-poly(methyl
methacrylate)100
(P(crown0.4-g-AA0.6)90-b-PMMA100) diblock copolymers were synthesized by amidation of
PAA90-b-PMMA100 with commercially-available 2-aminomethyl-18-crown-6. EDCI, 1-HOBt
and 2-aminomethyl-18-crown-6 were used (0.45 equivalent to acid unit) and the mixture was
allowed to undergo reaction for 24 hours. After dialysis for three days to remove byproducts
and unreacted compounds, the white powder-like product was obtained from lyophilization
with a 85% yield. 1H NMR confirmed that the conjugation efficiency was about 90%. IR:
3650-3020, 3020-2780, 1728, 1643, 1558, 1450, 1242, 1103, 964 cm−1. 1H NMR (DMF-d7,
ppm): δ 3.92-2.98 (br,-OCH2CH2O- and -OCH3), 2.76–1.26 (br,-CHCH2- of the polymer
backbone), 1.23-0.91 (s, CH3). 13C NMR (DMF-d7, ppm): δ 177.8, 176.4, 174.9, 72.0-67.4,
54.6-51.7, 44.6-41.3, 36.9-35.4. DSC: (Tg)PMMA = 120.8 , (Tg)crown-g-PAA = 157.2 . TGA in
N2: 310–410 °C, 47% mass loss; 410–500 °C, 12% mass loss, 35% mass remaining above
500 °C.
1
Submitted to
Poly(acrylic acid)75-b-polybutadiene104 (PAA75-b-PB104) diblock copolymers
PAA-b-PB diblock copolymer was purchased from Polymer Source, Inc. and used as received.
PDI = 1.10.
2,2’-(Ethylenedioxy)bis(ethylamine) (EDDA) was purchased from Sigma-Aldrich
Corporation. Dimethylformamide (DMF) was purchased from Acros Organics.
2. Sample preparation and characterizations
Complex nanoparticle assembly
PAA90-b-PMMA100 or P(crown0.4-g-AA0.6)90-b-PMMA100 and PAA75-b-PS104 diblock
copolymers at a certain blending ratio were first dissolved in DMF to produce a 0.1 weight
percent solution of block copolymer. Fast water addition was accomplished by simply
pipetting a certain amount of water into the polymer-DMF solution. After addition of a certain
amount of diamine EDDA, sample solutions were sealed in vials at ambient condition before
characterization. The time duration was recorded as aging time.
Transmission electron microscopy (TEM)
TEM imaging was performed on a Tecnai 12 microscope operating at an accelerating voltage
of 120 kV. TEM samples were prepared by applying a drop of polymer solution (about 2–4
ul) onto a carbon-coated copper TEM grid and allowing the solvents to evaporate under
ambient conditions. Images were collected on a Gatan CCD. A vapor staining method was
applied to TEM samples. Dried TEM grids were placed on a 25x75x1 mm glass slide to sit in
a sealed 100 mL glass bottle suspended above 1 mL 4 wt% osmium tetroxide aqueous
solution (purchased from Electron Microscopy Sciences). OsO4 vapor staining process lasted
from 6 hours to 24 hours for different samples.
1
H nuclear magnetic resonance (1H NMR)
1
H NMR spectra were recorded on an Inova 500 MHz spectrometer interfaced to a UNIX
computer using VnmrJ software.
Chemical shifts were referenced to the internal
3-trimethylsilylpropionate-d6 (TSP). The chemical shift of TSP was reported to be pH
dependent.[2] The chemical shifts of TSP were referenced to the internal acetone, and
showed no change over the pH range of the entire experiment.
Solution A was 0.4630 g of EDDA and 0.6020 g of acetic acid dissolved in 20 mL of D2O.
The molar ratio of amine to acid was 2.5 : 4, which was the final ratio in the polymer
self-assembly condition.
Solution B was 0.3320 g of 18-crown-6 dissolved in 10 mL of D2O. In the same volume of
respective solutions, the molar ratio of acetic acid to 18-crown-6 was 4:1, which was the ratio
in the polymer self-assembly condition.
Solution C was 0.938 g of potassium chloride dissolved in 10 mL of D2O. In the same
volume of respective solutions, the molar ratio of KCl to 18-crown-6 was 1:1.
The chemical shift of (CH2OCH2CH2NH3+)2 was 3.220 ppm in solution A. The changes of
this chemical shift were recorded as evidence of complexation and dissociation. Solution A
and solution B were mixed in the ratios of 1:0.25, 1:0.5, 1:0.75, 1:1, 1:1.5, 1:2; 1:2.5; 1:3, 1:4,
1:5, 1:6, among which the ratio of 1:1 mimicked the ratio of EDDA, PAA and crown ether
present in the polymer self-assembly condition (Figure 1). Solution A, solution B and
2
Submitted to
solution C were mixed in the ratios of 1:1:0.5, 1:1:1, 1:1:2, 1:1:3, 1:1:4, 1:1:5, among which
the ratio of 1:1:2 mimicked the ratio of the addition of KCl to trigger the dissociation.
3. Results and discussion
Figure S1. TEM image showing the co-existing nanoparticle chains and rings with dispersed
lengths and sizes from P(crown0.4-g-AA0.6)90-b-PMMA100 and PAA75-b-PB104 mixture with
added EDDA diamine (amine to PAA acid and crown ether side chain) molar ratio = 0.5:1.0).
Block copolymer mixing molar ratios (PMMA to PB volume ratio) are 1:1.5 (1:1). Samples
were aged for 1 day and stained by OsO4 before imaging.
1
Dayananda, K.; Dhamodharanm R. Journal of Polymer Science: Part A: Polymer
Chemistry, 2004, 42, 902-915
2 Wishart, D. S.; Bigam, C. G.; Yao, J.; Abildgaard, F.; Dyson, H. J.; Oldfield, E.; Markley,
J. L.; Sykes, B. D. Journal of Biomolecular NMR 1995, 6, 135-14
3