Supplementary Information

Supplementary Figure S1. Scheme of synthesis of various monomers.

2

Supplementary Figure S2. Scheme of synthesis of block copolymers.

3

Supplementary Figure S3. Plot of Mn vs. monomer to initiator ratio for a series of five different

polymerizations. The linear trend demonstrates these polymerizations are living within the

molecular weight ranges studied.

4

Supplementary Figure S4. AFM images of thin spun cast films. AFM was used to qualitatively

understand the phase separation as a function of the alkyl side chain length. As the side chain is

made longer, the phase separation improves. The C5 shows little contrast and is therefore not

shown.

5

Supplementary Figure S5. SAXS curve for the block copolymer before annealing. The two

peaks correspond to 1 and 3 , consistent with a cylindrical morphology. The SAXS pattern

does not change after thermal treatment.

6

Supplementary Figure S6. TGA of the C16 homopolymer and the diblock copolymer. The C16

homopolymer demonstrates the basic polymer is stable to above 350°C while the Cobalt

containing block copolymer has a thermal transition starting around 100°C. Using weight loss to

calculate carbonyl loss, it is determined that 94% of the carbonyl ligands have been evaporated.

7

Supplementary Figure S7. TGA of the cobalt-containing homopolymer. Similar to the block

copolymer, the carbonyl ligands are evaporated starting around 100°C and then backbone

degradation begins around 350°C. This sample contains 26 wt% of cobalt which is consistent

with the weight loss present at 200°C.

8

Supplementary Figure S8. Microtomed TEM image of the block copolymer before thermal

treatment. This is an unstained TEM image since the Cobalt containing minor phase provides

plenty of contrast. This end-on cylinder view is consistent with the SAXS curve collected for the

same sample.

9

Supplementary Figure S9. (left) Homopolymer before thermal treatment shows no contrast as

expected for a homogenous sample. (right) Homopolymer after thermal treatment shows small

black structures consistent with cobalt nanoparticle formation.

10

DSCN1080-1.wmv

Supplementary Movie S1. Movie demonstrating the response of thermally annealed both the

paramagnetic homopolymer and the room temperature ferromagnetic block copolymer to an

external magnet.

11

Supplementary Figure S10. Moment vs. Temperature for the thermally treated homopolymer

using both zero field cooling and field cooling at 100 Oe showing that the material is

paramagnetic. Because the material is paramagnetic, the data points overlap. The sample was not

demagnetized and used as it is for the experiments.

12

Supplementary Figure S11. Moment vs. Temperature for the thermally treated block

copolymer using both zero field cooling and field cooling at 100 Oe. The observed difference in

ZFC and FC is typical for ferromagnetic materials. The sample was not demagnetized and used

as it is for the experiments.

13

Supplementary Figure S12. The chemical state of cobalt was investigated by Near edge X-ray

absorption fine structure (NEXAFS) spectroscopy of the BCP and homopolymer before and after

heat treatment. The peak position of Co LIII edge is shifted to lower energy indicating the

decarbonylation of dicobalt hexacarbonyl after heat treatment in both homopolymer and block

copolymer. Further, the shape of the peaks (i.e. no splitting) after heat treatment is also

consistent with the cobalt foil (Coº species) reported in the literature. In NEXAFS of nanosized

cobalt particles, the Co LIII peak was shifted higher by 1.5eV than bulk cobalt foil.43

14

Supplementary Figure S13. TGA of the diblock copolymer containing the cobalt and ferrocene

monomers in the ratio x : y = 0.3 : 0.7. Similar to the cobalt containing block copolymer, the

carbonyl ligands are evaporated starting around 100°C and then backbone degradation begins

around 350°C. The weight loss at 200°C is 5%, which is in agreement with the theoretically

calculated amount of carbonyl ligands in the polymer. As the mol% of the cobalt containing

monomers changes (increases or decreases), the carbonyl loss changed accordingly.

15

Supplementary Figure S14: TGA of the ferrocene-containing homopolymer. The polymer is

completely inert at 200°C, the temperature used to evaporate the carbonyl ligands. Backbone

degradation begins around 350°C.

16

Supplementary Figure S15: To investigate whether the observed room temperature

ferromagnetic behavior was solely confined to the one block copolymer reported in the

manuscript, we prepared another block copolymer/homopolymer combination shown here and

below in Figure SI10b. We used ferrocene to ‘dilute’ the cobalt metal-containing block and to

ensure phase separation. This block copolymer self-assembles into a cylindrical phase and after

a thermal treatment at 200°C (ferrocene is completely stable) the resultant material is indeed a

room temperature ferromagnet as shown by the SQUID magnetometer data.

17

Supplementary Table

Supplementary Table S1. Characterization of Monocobalt-containing Block Copolymers

polymer Mn,GPC (kDa) Mw,GPC (kDa) n/ma fCob PDI

M1 82 91 137/59 0.32 1.11

M2 76 85 106/71 0.39 1.12

M3 73 82 83/83 0.50 1.12

M4 80 88 71/107 0.56 1.10

M5 74 83 48/112 0.65 1.12 a First, the molar ratios of two monomers were obtained from 1H NMR integration, and then

degree of polymerizations (DPs) were calculated using the Mn data from THF GPC. b Volume

fractions of Co-containing block were calculated based on density data obtained by density

column method.

18

Supplementary Methods

Experimental Section

General. Unless otherwise noted, all reagents were purchased either from Acros Organics,

Aldrich, or Strem and used without further purification. CH2Cl2 and THF were distilled over

CaH2 and Na0/benzophenone prior to use, respectively. Third generation Grubbs’ catalyst and

exo-oxanorbornene were synthesized according to the literature. The 1H NMR spectra were

recorded on a Bruker DPX-300 MHz spectrometer. Chemical shifts are expressed in δ (ppm)

using residual solvent protons or TMS as internal standard. Molecular weights and PDIs were

measured by GPC equipped with two-column sets (Polymer Laboratories) and RI detectors

(HP1047A) using THF as mobile phase with a flow rate of 1 mL/min, relative to polystyrene

standards.

General Synthesis Procedure for Compounds 2a, 3a and 5a. Compound 1a, alcohol

derivatives, and 1.1 equiv of triphenylphosphine, THF were added to a round-bottom flask. After

immersing the flask in an ice bath, 1.1 equiv of diisopropylazodicarboxylate (DIAD) was added

dropwise. The ice bath was then removed, and the reaction was allowed to stir at room

temperature for 24 h. The solvent was removed under reduced pressure by rotavap. The product

was purified by recrystallization or column chromatography.

Synthesis of Compound 2a. Compound 1a (4.44 g, 26.9 mmol), 1-hexadecanol (5.93 g, 24.5

mmol), triphenylphosphine (7.06 g, 26.9 mmol), diisopropylazodicarboxylate (DIAD) (5.33 ml,

26.9 mmol). The product was isolated and purified by recrystallization from methanol. The pure

product is a white solid. Yield: 8.57 g (22.0 mmol, 90%). 1H NMR (300 MHz, CDCl3): δ 6.50 (s,

19

2H), 5.26 (s, 2H), 3.45 (t, 2H), 2.82 (s, 2H), 1.56-1.38 (m, 2H), 1.28-1.10 (m, 26H), 0.88 (t, 3H).

13C NMR (75 MHz, CDCl3): δ 176.32, 136.55, 80.90, 47.38, 39.05, 31.94, 29.70, 29.68, 29.64,

29.56, 29.48, 29.38, 29.14, 27.62, 26.70, 22.71, 14.16. FAB-MS (m/z): [M]+ calculated

forC24H39NO3, 389.6; found, 389.3.

Synthesis of Compound 3a. Compound 1a (4.03 g, 24.4 mmol), progargyl alcohol (1.57 ml,

26.8 mmol), triphenylphosphine (7.04 g, 26.8 mmol), diisopropylazodicarboxylate (DIAD) (5.32

ml, 26.8 mmol). The product was isolated by recrystallization from diethyl ether, and then

purified by chromatography (SiO2, ethyl acetate/hexane = 3/2). The pure product is a white solid.

Yield: 4.45 g (21.9 mmol, 90%). 1H NMR (300 MHz, CDCl3): δ 6.50 (s, 2H), 5.25 (s, 2H), 4.20

(s, 2H), 2.91 (s, 2H), 2.17 (s, 1H). 13C NMR (75 MHz, DMSO-d6): δ 175.80, 137.00, 80.79,

78.14, 74.15, 47.71, 27.68. FAB-MS (m/z): [M]+ calculated for C11H9NO3, 203.2; found, 203.1.

Synthesis of Compound 4a. Compound 3a (2.04 g, 10.0 mmol) was dissolved in 50 ml CH2Cl2

in a round-bottom flask, and Co2(CO)8 (6.87 g, 20.0 mmol) was added when the flask was

immersed in an ice bath. The reaction mixture was allowed to stir in the ice bath for 2 h and at

room temperature for another 2 h. After reaction, the solvent was removed under nitrogen flow.

Pentane (150ml) was then added to dissolve the excess of Co2(CO)8 and to precipitate the

product. The pure product was obtained by chromatography (SiO2, CH2Cl2/ acetone = 9/1), as a

red solid. Yield: 3.67 g (7.5 mmol, 75%). 1H NMR (300 MHz, CDCl3): δ 6.50 (s, 2H), 6.00 (s,

1H), 5.27 (s, 2H), 4.80 (s, 2H), 2.89 (s, 2H). 13C NMR (75 MHz, DMSO-d6): δ 199.50, 176.35,

137.01, 90.00, 80.78, 73.92, 47.57, 41.12. ESI-MS (m/z): [M]+ calculated for C17H9NO9Co2,

489.1; found, 488.9.

20

Synthesis of Compound 5a. Compound 1a (2.0 g, 12.2 mmol), ferrocene methanol (2.88g, 13.4

mmol), triphenylphosphine (3.50 g, 13.4 mmol), diisopropylazodicarboxylate (DIAD) (2.7 ml,

13.4 mmol). The product was isolated by precipitation from diethyl ether, and then purified by

chromatography (SiO2, ethyl acetate/hexane = 2/3). The pure product is obtained by

recrystallization from methanol. The final product is a yellow solid. Yield: 1.62 g (4.46 mmol,

37%). 1H NMR (300 MHz, CDCl3): δ 6.47 (s, 2H), 5.23 (s, 2H), 4.39 (s, 2H), 4.26 (d, 2H), 4.15

(s, 5H), 4.08 (d, 2H), 2.76 (s, 2H). 13C NMR (75 MHz, CDCl3): δ 175.78, 136.60, 81.83, 80.89,

69.36, 68.75, 68.31, 47.52, 39.28. FAB-MS (m/z): [M]+ calculated forC19H17NFeO3, 363.2;

found, 363.1.

General Procedure for Block Copolymer Synthesis with Cobalt metal Block. Known

amounts of monomers 2a and 4a were added into two separate Schlenk flasks under an

atmosphere of nitrogen, and dissolved in anhydrous CH2Cl2 (1 ml per 100 mg of monomer). A

desired amount of third generation Grubbs’ catalyst was added into another Schlenk flask,

flushed with nitrogen, and dissolved in a minimum amount of anhydrous CH2Cl2. All three

solutions were degassed three times by freeze-pump-thaw cycles. First, monomer 2a was

transferred to the flask containing the catalyst via cannula. The reaction mixture was stirred

vigorously for 5 minutes, after which an aliquot was taken for GPC analysis, and monomer 4a

was transferred to the flask via a cannula. The polymerization was allowed to continue for

another 5 minutes, and then quenched with 0.2 ml of ethyl vinyl ether. An aliquot was taken for

GPC analysis, and the remaining product was precipitated from methanol.

21

General Procedure for Block Copolymer Synthesis with Cobalt and Ferrocene metal Block

(Dilution Studies): Known amounts of monomers 4a and 5a were mixed and added into a single

Schlenk flask under an atmosphere of nitrogen, and dissolved in anhydrous CH2Cl2 (1 ml per 100

mg of monomers). A desired amount of third generation Grubbs’ catalyst and Compound 2a

were added into separate Schlenk flasks, flushed with nitrogen, and dissolved in a minimum

amount of anhydrous CH2Cl2. All three solutions were degassed three times by freeze-pump-

thaw cycles. First, monomer 2a was transferred to the flask containing the catalyst via cannula.

The reaction mixture was stirred vigorously for 6 minutes, after which an aliquot was taken for

GPC analysis, and then the solution containing monomer 4a and 5a was transferred to the flask

via a cannula. The polymerization was allowed to continue for another 8 minutes, and then

quenched with 0.2 ml of ethyl vinyl ether. An aliquot was taken for GPC analysis, and the

remaining product was precipitated from methanol.

Block Copolymer M1. 1H NMR (300 MHz, CDCl3): δ 6.20-5.96 (br, 1H), 5.92-5.62 (br,

1.11H), 5.20-4.90 (br, 1.12H), 4.90-4.70 (br, 0.66H), 4.64-4.32 (br, 0.71H), 3.64-3.12 (m,

2.94H), 1.80-0.50 (m, 18.56H). 13C NMR (75 MHz, CDCl3): δ 199.9, 176.0, 132.5, 117.7, 53.5,

32.0, 29.7, 27.7, 26.8, 22.7, 14.1. GPC: Mn = 82 kDa, Mw/Mn = 1.11.

Block Copolymer M2. 1H NMR (300 MHz, CDCl3): δ 6.20-5.96 (br, 1H), 5.94-5.62 (br,

1.06H), 5.20-4.90 (br, 1.09H), 4.90-4.70 (br, 0.68H), 4.64-4.32 (br, 0.63H), 3.64-3.12 (m,

2.60H), 1.80-0.50 (m, 15.14H). 13C NMR (75 MHz, CDCl3): δ 199.9, 176.0, 132.5, 117.7, 53.5,

32.0, 29.7, 27.7, 26.8, 22.7, 14.1. GPC: Mn = 76 kDa, Mw/Mn = 1.12.

22

Block Copolymer M3. 1H NMR (300 MHz, CDCl3): δ 6.20-5.92 (br, 1H), 5.92-5.58 (br,

1.12H), 5.20-4.90 (br, 1.13H), 4.90-4.64 (br, 0.95H), 4.64-4.30 (br, 0.66H), 3.64-3.09 (m,

2.54H), 1.80-0.50 (m, 13.44H). 13C NMR (75 MHz, CDCl3): δ 199.9, 176.0, 132.5, 117.7, 53.5,

32.0, 29.7, 27.7, 26.8, 22.7, 14.1. GPC: Mn = 73 kDa, Mw/Mn = 1.12.

Block Copolymer M4. 1H NMR (300 MHz, CDCl3): δ 6.28-5.95 (br, 1H), 5.95-5.60 (br,

0.99H), 5.22-4.92 (br, 1.03H), 4.92-4.65 (br, 0.90H), 4.65-4.30 (br, 0.50H), 3.68-3.10 (m,

1.99H), 1.80-0.50 (m, 8.33H). 13C NMR (75 MHz, CDCl3): δ 199.9, 176.0, 132.5, 117.7, 53.5,

32.0, 29.7, 27.7, 26.8, 22.7, 14.1. GPC: Mn = 80 kDa, Mw/Mn = 1.10.

Block Copolymer M5. 1H NMR (300 MHz, CDCl3): δ 6.24-5.94 (br, 1H), 5.94-5.60 (br,

0.99H), 5.21-4.92 (br, 1.04H), 4.92-4.65 (br, 1.04H), 4.65-4.30 (br, 0.48H), 3.66-3.10 (m,

1.79H), 1.80-0.50 (m, 5.93H). 13C NMR (75 MHz, CDCl3): δ 199.9, 176.0, 132.5, 117.7, 53.5,

32.0, 29.7, 27.7, 26.8, 22.7, 14.1. GPC: Mn = 74 kDa, Mw/Mn = 1.12.

TEM Sample Preparation: Samples for TEM were prepared by drop-casting a 10 wt %

toluene solution into a teflon mold, the sample was then solvent annealed in benzene for two

weeks, embedded in an epoxy resin, and cured at 60°C for 24 hours. Ultra thin sections were

then cut with a diamond knife using a Leica Ultracut microtome. TEM analysis was conducted

on a JEOL 100CX TEM operating at an accelerating voltage of 100 kV. For samples studied

after annealing, the samples were heated to 200°C after solvent annealing but before epoxy

treatment.

23

SAXS Sample Preparation: Small angle x-ray scattering samples were prepared by drop-

casting a 10 wt % toluene solution into a teflon mold, the sample was then solvent annealed in

benzene for two weeks. The calculated center-to-center d-spacing of microdomains was found to

be 40 nm.

Magnetic Measurements: Based on the Ms value of 3.5 emu/g of block copolymer and the fact

that it contains ~14 wt% cobalt, the Ms is 25 emu/g of cobalt, or 1475 emu/mole of cobalt

compared to bulk cobalt which is 166 emu/g, or 9700 emu/mole of cobalt.44,45

Supplementary References

43 Papaefthimiou, V. et al. Nontrivial Redox Behavior of Nanosized Cobalt: New Insights

from Ambient Pressure X-ray Photoelectron and Absorption Spectroscopies. ACS Nano,

(2011).

44 Miller, J. S. & Epstein, A. J. Organic and Organometallic Molecular Magnetic Materials -

Designer Magnets. Angewandte Chemie International Edition In English 33, 385-415,

(1994).

45 Salavati-Niasari, M., Davar, F., Mazaheri, M. & Shaterian, M. Preparation of cobalt

nanoparticles from [bis(salicylidene)cobalt(II)]-oleylamine complex by thermal

decomposition. J Magn. Magn. Mat. 320, 575-578, (2008).