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1

Supplementary Information

Corona Liquid Crystalline Order Helps to Form Single Crystals

When Self-Assembly Takes Place in the Crystalline/Liquid

Crystalline Block Copolymers

Zaizai Tong,a,b,c

Yanming Li, a

Haian Xu,a Hua Chen,

a Weijiang Yu,

a Wangqian

Zhuo,a Runke Zhang,

a Guohua Jiang

a,b,c,*

a Department of Materials Engineering, Zhejiang Sci-Tech University, Hangzhou

310018, P. R. China

b National Engineering Laboratory for Textile Fiber Materials and Processing

Technology (Zhejiang), Hangzhou 310018, P. R. China

c Key Laboratory of Advanced Textile Materials and Manufacturing Technology

(ATMT), Ministry of Education, Hangzhou 310018, P. R. China.

2

Experimental Section

Materials. 2-(Dimethylamino)ethyl methacrylate (DM) was passed through a basic

Al2O3 column prior to use to remove the inhibitor. ε-Caprolactone was dried over

CaH2 and distilled under reduced pressure. Tetrahydrofuran (THF) and toluene for

polymerization were refluxed with sodium flakes and freshly distilled. Copper

bromide was washed with acetic acid and diethyl ether for several times and dried

under vacuum. Stanneous 2-ethylhexanoate (Sn(Oct)2) (99%) was purchased from

Acros and distilled under reduced pressure to remove the water prior to use.

Bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) and methyl orange (MO) were

purchased from Aladdin without any treatment. The other commercially available

chemicals were used without further purification. The details for synthesis of initiator

2-hydroxyethyl 2-bromo-2-methylpropanoate (2-HBMP) were described in

elsewhere.1

Sample Synthesis

Synthesis of PDM homopolymer. PDM homopolymer was synthesized via atom

transfer radical polymerization (ATRP) using 2-HBMP initiator. The detailed

synthetic process is given below. In a Schlenk flask, 2-HBMP (100 µL, 0.70 mmol),

12 mL DM monomer (71 mmol), 1,1,4,7,10,10-hexamethyltriethylenetetramine

(HMTETA) (180 μL, 0.78 mmol), fresh distilled THF (15.0 mL) were mixed and

stirred for 10 min under nitrogen protection. The mixture was immediately frozen in

liquid nitrogen, and a vacuum was applied. After 3 freeze-thaw cycles, CuBr (100 mg,

3

0.70 mmol) was added under N2. Then the flask was put into an oil bath at 65 C for 3

h. Polymerization was quenched into liquid nitrogen and the product was dissolved in

THF and passed through an alumina column to remove the metal complex. After

being concentrated, the THF solution was precipitated in n-hexane. The purification

was repeated thrice and the obtained sample was further dried in a vacuum oven

overnight at 40 C. The polymerization degree of DM is 42 estimated from 1H NMR.

Synthesis of PCL-Br ATRP Macroinitiator. PCL-Br macroinitiator was

synthesized via the ring opening polymerization (ROP) of ε-CL in anhydrous toluene

using 2-HBMP as the initiator and Sn(Oct)2 as the catalyst. In a typical example,

HBMP (121 µL, 0.85 mmol), ε-CL (10.0 mL, 85.2 mmol), and 20 mL of dry toluene

were added into a Schlenk flask equipped with a magnetic stirring bar under nitrogen

atmosphere. Then the tube was immersed in an oil bath with a temperature of 110 C.

Polymerization was initiated after 10 min by injecting a solution of the catalyst

Sn(Oct)2 in toluene corresponding to 0.1 mol% of the monomer. Polymerization was

terminated after 24 h by cooling to room temperature. The reaction mixture was

diluted with tetrahydrofuran (THF) and then precipitated into an excess of methanol

thrice. Finally, the precipitates were collected by filtration and dried in a vacuum oven

at 40 C.

Synthesis of PCL-b-PDM. Atom transfer radical polymerization (ATRP) was

chosen to prepare the diblock copolymers. The detailed synthetic process is given

below. In a Schlenk flask, 300 mg of PCL macroinitiator, 500 μL DM monomer,

1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) (30 μL), fresh distilled

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THF (4.0 mL) were mixed and stirred for 10 min under nitrogen protection. The

mixture was immediately frozen in liquid nitrogen, and a vacuum was applied. After 3

freeze-thaw cycles, CuBr (5.34 mg) was added under N2. Then the flask was put into

an oil bath at 65 C for 2 h. Polymerization was quenched into liquid nitrogen and the

product was dissolved in THF and passed through an alumina column to remove the

metal complex. After being concentrated, the THF solution was precipitated in

n-hexane. The purification was repeated thrice and the obtained sample was further

dried in a vacuum oven overnight at 40 C.

Quaternization of Block Copolymers. The block copolymers, PCL-b-PDM, were

quaternized according to a literature procedure.2 The preparation of PCL170-b-qPDM22

is given as an example. A clear solution of PCL170-b-PDM22 (80.7 mg, eq DM=0.078

mmol) in nitromethane (10 mL) was stirred for 10 min in a Schlenk flask under

nitrogen flow. Then iodomethane (50 equiv, 243 μL), dissolved in 4 mL of

nitromethane, was added dropwise under nitrogen. The solution became slightly

yellow after iodomethane was completely added. The reaction was continued for 2

days under reflux. The mixture was then concentrated and dissolved in DMF, dialyzed

against deionized water for 3 days to remove the organic solvent. Finally, the product

was then freeze-dried for 1 day and vacuum-dried at 50 °C for another 2 days.

Complexation Between Bis(2-ethylhexyl) Sulfosuccinate Sodium Salt (AOT)

and PCL-b-qPDM. The preparation of PCL-b-qPDM/AOT is given as an example.

PCL-b-qPDM was dissolved in DMF in a Schlenk flask, to which 1.05 equiv of AOT

dissolved in DMF was then added. The solution was stirred at room temperature for

5

30 min to ensure completely dissolved. Then the solution was poured into an excess

of deionized water and the complexed product, PCL-b-qPDM/AOT, was precipitated

from the solution. The obtained product was washed with deionized water for several

times to remove residual AOT molecules. And the purification was repeated thrice by

precipitation. Energy dispersive analysis (EDS) showed the absence of Na+ and I

−,

indicating essentially complete (stoichiometric) complexation with no excess AOT.

Characterization. The molecular weight and the polydispersity index (PDI) were

evaluated by gel permeation chromatography (GPC) using a Waters system calibrated

with standard polymethyl methacrylate. DMF with 1% lithium bromide (LiBr) was

used as an eluent at a flow rate of 1.0 mL min−1

. 1H NMR spectra were recorded on a

Bruker DMX-400 MHz. A FEI Quanta 200 FEG environmental scanning electron

microscope equipped with an energy dispersive spectrometer (EDS) was used to

verify the presence or absence of Na+ and I

− in the complexes. The UV-Vis spectra of

the samples were recorded on a Hitachi U-3010 spectrophotometer. TEM

observations were carried out using a JEOL JEM-1230 electron microscope at an

acceleration voltage of 80 kV. TEM samples were prepared by dropping 4 μL of the

micellar solution onto carbon-coated copper grids. Tapping mode atomic force

microscopy (AFM) was conducted on an XE-100E instrument (PSIA cooperation,

Korea). A drop of micellar solution was deposited on a piece of silicon wafer and

spin-coated at 3000 r min-1

for 30 s and the thickness of single crystals was measured.

Wide-angle X-ray diffraction scattering (WAXS) experiments were performed at

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BL16B1 beamline in Shanghai Synchrotron Radiation Facility (SSRF) in China. The

wavelength of X-ray was 1.24 Å, and the sample-to-detector distance was set as 358

mm. Solution samples for WAXS measurement were sandwiched between two

polyimide membranes and transmittance mode was carried out. Dried samples for

WAXS measurement were collect by centrifugation of micellar solution at 15000 r

min-1

for 1 h and finally vacuum-dried for 1 day to remove residual solvent.

Two-dimensional (2D) WAXS patterns at room temperatures were recorded. The 2D

WAXS patterns were converted into one-dimensional (1D) WAXS profiles using

Fit2D software.

Preparation of the Micellar Solution. The complexed diblock copolymers were first

dissolved in DMF to obtain a homogeneous solution with a concentration of 1 mg/mL.

Then methanol was added very slowly (5 mL/h) to the solution while stirring until the

volume ratio of methanol and DMF in the solution was reached in a preset ratio. After

complete crystallization, the solution was dialyzed against methanol to remove the

DMF and the final solution concentration was 0.2 mg/mL.

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13 14 15 16

Rotention time (min)

PCL-Br

PCL170

-b-PDM22

PCL170

-b-PDM35

PCL170

-b-PDM72

(a)

13 14 15 16 17

Retention time (min)

PCL70

PCL70

-b-PDM17

PCL70

-b-PDM32

(b)

Figure S1. GPC traces of two series of PCL based block copolymers, (a) PCL170 based BCPs and

(b) PCL70 based BCPs.

Table S1. Molecular Characteristics of PCL, PDM and Various BCPs

Polymers a)

Mn b)

(g/mol) PDI b)

Complexed BCPs fPCL c)

PCL70 11600 1.07

PCL70-b-PDM17 14500 1.13 PCL70-b-qPDM17/AOT 0.44


PCL170 26600 1.08




PCL170-b-PDM85 38200 1.17 0.59 d)

PDM42 8200 1.09 qPDM42/AOT a)

Composition was estimated from 1H NMR spectra.

b) Number average molecular weights and PDI were characterized from GPC.

c) Weight fraction of PCL in complexed PCL-b-qPDM/AOT.

d) Weight fraction of PCL in common diblock copolymer, PCL170-b-PDM85.

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Figure S2. The EDS analysis spectrum of PCL170-b-qPDM22/AOT.

0.0 0.2 0.4 0.6 0.8 1.00.4

0.5

0.6

0.7

0.8

0.9

1.0

Tra

nsm

itta

nce

Methanol content (Vmethanol

/Vsolution

)

Figure S3. The transmittance of 1 mg/mL PCL170-b-qPDM22/AOT DMF solution on

the methanol content during the methanol dropping process.

Figure S4. TEM micrographs of PCL170-b-qPDM22/AOT at different methanol/DMF

ratios. The methanol/DMF ratio is indicated in the figures.

Element Wt % mol %

C 66.60 72.64

N 3.89 3.67

O 25.12 20.35

S 7.72 3.24

Na 0.09 0.05

I 0.47 0.05

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Figure S5. AFM height image and corresponding of the profile of

PCL170-b-qPDM72/AOT, and the thickness of the single crystals is 13 nm.

It indicates that the PCL blocks crystallize under the present condition of assembly,

and the solvent-soluble qPDM/AOT chains distribute on the top and bottom basal

surfaces of the PCL cores. Based on the method reported by Cheng et al., the formula

below is used to calculate the thickness of PCL layer.

/

/

/ ( )

/ ( ) /

PCL c c a a

n PCL PCL PCL PCLPCL overrall PCL c c a a qPDM AOT

n PCL PCL PCL PCL n qPDM AOT

M W Wd d

M W W M

Here, the physical meanings of the parameters in the formula are expounded in Table

S2. To simplify the calculation, the crystallinity of PCL is set to be 1 and the density

of the block is around 1 g/cm3 as summarized in Table S2. Therefore, based on the

above equation, the thickness of individual PCL and qPDM/AOT layers is estimated

to be 4.4 and 4.3 nm, respectively.

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Table S2. The physical meanings of the parameters in the formula.

Parameter Physical meaning Value

dPCL The thickness of PCL lamella 4.4 nm

doverall The thickness of overall lamella 13 nm

𝑀𝑛𝑃𝐶𝐿 Mn of PCL block 19400

𝑀𝑛𝑞𝑃𝐷𝑀/𝐴𝑂𝑇

Mn of qPDM/AOT block 31200

𝑊𝑃𝐶𝐿𝑐 The crystallinity of PCL 1

𝜌𝑃𝐶𝐿𝑐 The density of crystalline PCL 1.2 g/cm

3

𝑊𝑃𝐶𝐿𝑎 The content of amorphous PCL 0

𝜌𝑃𝐶𝐿𝑎 The density of amorphous PCL 1.0 g/cm

3

𝜌𝑞PDM/AOT The density of qPDM/AOT ～1 g/cm3

1 2 3 4

Inte

ns

ity (

a.u

.)

2

25 wt%

33 wt%

50 wt%

weak peak

LC3.0 nm

(a)

1 2 3 4

Inte

ns

ity (

a.u

.)

2

33 wt%

50 wt%

(b)

Figure S6. WAXS profiles of (a) qPDM42/AOT at various weight fractions in the

methanol/DMF (ratio=2) solution, (b) qPDM42/AOT0.5/MO0.5.

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10 12 14 16 18 20 221.5 2.0 2.5 3.0 3.5 4.0

Inte

nsit

y (

a.u

.)

weak peak

2

BCP=50 mg, DMF=0.5 mL, methanol=0.5 mL



(110)PCL

Figure S7. Selected WAXS profiles of PCL170-b-qPDM22/AOT at indicated volume of

dropping methanol. The initial BCP concentration is indicated in the figure.

Figure S8. Morphologies of PCL170-b-qPDM22/AOT at various organic solvents. a)

methanol, b) ethanol, c) corresponding AMF height images in ethanol, size 1.5×1.5

μm, inset is the height information of the single crystal, d) n-butanol and e) n-hexanol.

a)-e) the cosolvent is DMF and f) THF.

The effect of different alcohols on the final morphology of PCL170-b-qPDM22/AOT

was probed. One can see that, in methanol, single crystals with large axial ratio are

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shown in Figure S8a. For ethanol, the self-assembled morphology shows single

crystals with smaller size (Figure S8b). The height information of this platelet is

further examined by the AFM measurement, and the thickness of the crystals is about

10 nm (Figure S8c inset). In n-butanol and n-hexanol, ribbon-like micelles (Figure

S8d) and irregular aggregates (Figure S8e) are existed, respectively, indicating

crystallization driving force becomes weak as solvent from methanol to n-hexanol.

Figure S8 indicate that solvent quality is a key factor to determine the final micellar

morphologies. The effect of solvents on the morphologies may result from the

solubility of the organic solvents toward the PCL block. The solubility parameters for

PCL and different organic solvents are listed in Table S3. As one can see that

methanol has a lowest solubility for PCL because the solubility parameters of

methanol and PCL are quite different. By contrast, the solubility parameter of

n-hexanol is very close to that of PCL, therefore PCL is difficult to crystallize in the

presence of selective solvent, n-hexanol. As a result, irregular aggregations in small

size are assembled. This phenomenon can be further reproduced by changing the good

solvent, DMF, to THF. Because PCL block is more soluble in THF than in DMF

(Table S3), thus crystallization of PCL will be retarded in the presence of THF. One

can see that spherical micelles of PCL170-b-qPDM22/AOT are formed at

methanol/THF=2:1 (Figure S8f), indicating crystallization of PCL is severely

retarded.

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Table S3. Solubility Parameters of Different Solvents and PCL

Solvent PCLa)

methanolb)

ethanolb)

n-butanolb)

n-hexanolb)

DMFb)

THFb)

δ (cal/cm3)

1/2 9.9 14.5 12.7 11.4 10.7 12.1 9.9

a) Calculated according to reference 3

b) Refer to 4

References:

(1) Tong, Z. Z.; Wang, R. Y.; Huang, J.; Xu, J. T.; Fan, Z. Q. Regulation of the

Self-Assembly Morphology of Azobenzene-Bearing Double Hydrophobic Block

Copolymers in Aqueous Solution by Shifting the Dynamic Host-Guest Complexation.

Polym. Chem. 2015, 6, 2214-2225.

(2) Wang, X.; Vapaavuori, J.; Zhao, Y.; Bazuin, C. G. A Supramolecular Approach to

Photoresponsive Thermo/Solvoplastic Block Copolymer Elastomers. Macromolecules

2014, 47, 7099-7108.

(3) Bordes, C.; Fréville, V.; Ruffin, E.; Marote, P.; Gauvrit, J. Y.; Briançon, S.; Lantéri,

P. Determination of Poly(ε-caprolactone) Solubility Parameters: Application to

Solvent Substitution in a Microencapsulation Process. Int. J. Pharm. 2010, 383,

236-243.

(4) Barton, A. F. M., Crc Handbook of Solubility Parameters and Other Cohesion

Parameters. CRC Press: New York, 1983.

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