Supporting information

Sensitive and reliable detection of glass transition of polymers

by fluorescent probes based on AIE luminogens

Suping Bao,a Qihua Wu,a Wei Qin,b Qiuling Yu,a Jing Wang,a Guodong Liang*,a and

Ben Zhong Tang*,b

aDSAP lab, PCFM lab, GDHPPC lab, School of Chemistry and Chemical Engineering, Sun Yat-Sen

University, Guangzhou 510275, China.

bHKUST-Shenzhen Research Institute, No. 9 Yuexing 1st RD, South Area, Hi-tech Park, Nanshan,

Shenzhen, China 518057; Department of Chemistry, Institute for Advanced Study, Division of

Biomedical Engineering and Institute of Molecular Functional Materials, The Hong Kong University of

Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Guangdong Innovative

Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent

Materials and Devices, South China University of Technology, Guangzhou 510640, China.

40 60 80 100 120

PS/TPE PS

Tg=89.5 C

endo

Temperature (oC)

Fig. S1 DSC curves of PS and PS/TPE (containing 1.0 wt% TPE) at heating rate of 1

ºC/min.

Electronic Supplementary Material (ESI) for Polymer Chemistry.This journal is © The Royal Society of Chemistry 2015

2.7 Å

2.3 Å

Scheme S1 Geometric strucutre of TPE. Size of phenyl rings was estimated to be 2.3

× 2.7 Å2 using ChemBioDraw Ultra 12.0.

40 60 80 100 120 140

Tg=110 C

endo

Temperature (oC)

Fig. S2 DSC curve of PMMA at heating rate of 1 ºC/min.

Temperatue dependence of elastic modulus of polymers.

Fig. S3 Temperature dependence of elastic modulus of polymers taken from ref 1.

DSC traces for determination of Tg.

A B

C D

Fig. S4 DSC traces for determination of Tg. Downloaded from internet at (A)

http://eurjmin.geoscienceworld.org/content/19/5/657/F2.large.jpg, (B) http://www.

intechopen.com/source/html/16714/media/image13.jpg, (C) http://www2.vtt.fi/inf/

julkaisut/publications/2005/summary/p563/figure8.jpg, and (D) http://www.beilstein-

journals.org/bjoc/content/figures/1860-5397-7-75-5.png?scale=2.2&max-

width=1024&background=FFFFFF.

It is difficult to acurately determine Tg from the DSC curves above (Fig. S4).

Measuring glass transition temperautre (Tg) by DSC.

Fig. S5 Measuring glass transition temperautre (Tg) by DSC. Downloaded from

internet at http://upload.wikimedia.org/wikipedia/en/1/16/Tgdscenglish.svg. Glass

transition takes place in a temperature range, as shown in Figue S8. Different

operational definitions of Tg are used, but all definitions are arbitary. For example,

some researchers defined the point A on the curve (Figue S3) as Tg, while others

insisted on the point B as Tg.

Synthesis.

Synthesis of tetraphenylethene (TPE).

A three-necked flask equipped with a magnetic stirrer was charged with zinc powder

(7.85 g; 120 mmol) and 150 mL THF under N2 atmosphere. The mixture was cooled

to -5 to 0 °C, and TiCl4 (6.5 mL; 60 mmol) was slowly added by a syringe under 10

°C. The mixture was restored to room temperature and stirred for 0.5 h, then reflux

for 2.5 h. The mixture was cooled to -5 to 0 °C, charged with pyridine (2.5 mL; 30

mmol) and stirred for 10 min. To the mixture was added 4.37 g benzophenone (24

mmol). The reaction mixture was refluxed for 24 h until the benzophenone was

consumed (followed by TLC). The reaction was quenched with 20 mL of 10% K2CO3

aqueous solution, and filtrated to remove solid. The product was extracted with

dicholomethane (3 × 50 mL). The organic layers were combined, washed with

saturated brine solution and dried over anhydrous magnesium sulphate. The solvent

was removed under reduced pressure to yield crude product. The crude product was

purified by silica chromatography using hexane as eluent to give the desired products

of tetraphenylethene (TPE). The compound emitted efficiently blue light under 365

nm radiation. 1H NMR (400 MHz, CDCl3), δ (TMS, ppm): 6.97.0 (m, 12 H, ArH),

7.07.2 (m, 8H, ArH). The 1H NMR spectrum agreed with literature data.2, 3

O

Zn, TiCl4

THF, reflux

Scheme S2 Synthetic route for tetraphenylethene (TPE).

Synthesis of ethyl 4-(1,2,2-triphenylvinyl)benzoate (TPE-C2).

1-(4-Bromophenyl)-1,2,2-triphenylethene (1). The compound was synthesized

according to the synthetic route shown in Scheme S3. Typical procedures were shown

as follows. To a solution of diphenylmethane (2.02 g; 12 mmol) in dry

tetrahydrofuran (50 mL) was added 6.25 mL of a 1.6 M solution of n-butyllithium in

hexane (10 mmol) at -78 °C under nitrogen. The resulting orange-red solution was

stirred for 30 min at that temperature. To this solution was added 4-

bromobenzophenone (2.35 g; 9 mmol). Afterwards, the reaction mixture was allowed

to warm to room temperature and stirred for another 6 h. The reaction was quenched

with the addition of an aqueous solution of ammonium chloride. The organic layer

was then extracted with dichloromethane (3 × 50 mL). The organic layers were

combined, washed with saturated brine solution and dried over anhydrous magnesium

sulphate. After solvent evaporation, the resulting crude alcohol (containing excess

diphenylmethane) was subjected to acid-catalyzed dehydration without further

purification. The crude alcohol was dissolved in about 80 mL of toluene in a 100 mL

Schlenk flask fitted with a Dean-Stark trap. A catalytic amount of p-toluenesulfonic

acid (342 mg; 1.8 mmol) was added and the mixture was refluxed for 34 h. After the

reaction mixture was cooled to room temperature, the toluene layer was washed with

10% aqueous NaHCO3 solution (2 × 25 mL) and dried over anhydrous magnesium

sulfate. Evaporation of the solvent under reduced pressure afforded the crude

tetraphenylethene derivative, which was further purified by silica gel column

chromatography using hexane as eluent. Yield 92%. 1H NMR (400 MHz, DMSO-d6),

δ (TMS, ppm): 6.957.11 (m, 17 H, ArH), 7.32 (d, 2H, ArH).

n-BuLi OH

Br

Br CO2H

2. CO2

1 TPE-CO2H

THF, -78 oC

Li

O

Br

THF, -78 oC

PTSAtoluene

1. n-BuLi,

TPE-C2 OO

DCC

ethanol

Scheme S3 Synthetic route for ethyl 4-(1,2,2-triphenylvinyl)benzoate (TPE-C2).

4-(1,2,2-Triphenylvinyl)benzoic acid (TPE-CO2H). To a solution of 1 (1.6 g;

3.89 mmol) in 30 mL dry THF was added dropwise 2.9 mL (4.64 mmol) of n-

butyllithium (1.6 M in n-hexane) at -78 °C under stirring. The reaction mixture was

stirred for 2 h to get a dark brown solution. To the obtained solution was then added

dry ice pieces in small portions under nitrogen. The solution was allowed to warm to

room temperature and stir for additional 12 h. The solvent was evaporated under

reduced pressure. The crude product was purified on a silica-gel column using

dichloromethane/methanol mixture (90/10 v/v) as eluent. Yield 85%. 1H NMR (400

MHz, DMSO-d6), δ (TMS, ppm): 6.957.11 (m, 17 H, ArH), 7.66 (d, 2H, ArH).

13C NMR (400 MHz, CD3OD), δ (TMS, ppm): 125.9, 126.8, 128.3 and 130.3 (Ar),

142.4 and 141.8 (C=C), 148.1 (Ar), 167.8 (CO2H). HRMS (MALDF-TOF): m/z

376.1458 (M+, calcd 376.1463).

Ethyl 4-(1,2,2-triphenylvinyl)benzoate (TPE-C2). 0.376 g TPE-CO2H (1 mmol)

was dissolved in 10 mL anhydrous DMF. To the solution was added 5 mL (2 mmol)

ethanol and 0.206 g (1 mmol) DCC at 0 °C under nitrogen. The solution was stirred

for 2 h at 0 °C, and was allowed to restore to room temperature. The solution was

stirred at room temperature overnight. The solvent was removed under reduced

pressure to yield crude product. The crude product was further purified by silica gel

column chromatography using dichloromethane/methanol mixture (90/10 v/v) as

eluent. Yield 82%. 1H NMR (400 MHz, CDCl3), δ (TMS, ppm): 1.36 (t, 3H,CH3),

4.32 (dd, 2H, CH2CH3), 6.907.10 (m, 19H, ArH), 7.93 (s, 2H, ArH). HRMS

(MALDF-TOF): m/z 405.15 [(M+1)+, calcd 404.18].

Synthesis of 2-(tetraphenylethoxy)ethanol (TPE-C2OH).

To a solution of 3.94 g 4-hydroxybenzophenone (20 mmol) and 4.14 g potassium

carbonate (30 mmol) in 50 mL acetone was added 2.84 mL 2-Bromoethanol (40

mmol). The mixture was refluxed under stirring for 24 h. After filtration and solvent

evaporation, the crude product was purified by a silica gel column using chloroform

as eluent to get compound 2. 1H NMR (400 MHz, CDCl3), δ (TMS, ppm): 4.0 (t, 2H,

CH2OH), 4.18 (t, 2H, OCH2CH2), 6.90 (d, 2H, ArH), 7.48 (t, 2H, ArH), 7.56 (t, 1H,

ArH), 7.74 (d, 2H, ArH), 7.82 (d, 2H, ArH).

O

OH

BrOH

O

OOH

K2CO3, Acetonreflux

OHO

O

2TPE-C2OH

Scheme S4 Synthetic route for 2-(tetraphenylethoxy)ethanol (TPE-C2OH).

A three-necked flask equipped with a magnetic stirrer was charged with zinc

powder (7.85 g; 120 mmol) and 150 mL THF under N2 atmosphere. The mixture was

cooled to -5 to 0 °C, and TiCl4 (6.5 mL; 60 mmol) was slowly added under 10 °C.

The mixture was restored to room temperature and stirred for 0.5 h, then reflux for 2.5

h. The mixture was cooled to -5 to 0 °C, charged with pyridine (2.5 mL; 30 mmol)

and stirred for 10 min. To the mixture were added 2.62 g benzophenone (14.4 mmol)

and 2.90 g compound 2 (12 mmol). The reaction mixture was refluxed until the

carbonyl compounds were consumed (followed by TLC). The reaction was quenched

with 10% K2CO3 aqueous solution, and filtrated to remove insoluble solid. The

product was extracted with dicholomethane (3 × 50 mL). The organic layers were

combined, washed with saturated brine solution and dried over anhydrous magnesium

sulphate. The solvent was removed under reduced pressure to yield crude product.

The crude product was purified by silica chromatography using chloroform as eluent

to give the desired products of 2-(tetraphenylethoxy)ethanol (TPE-C2OH). The

compound emitted efficiently blue light under 365 nm radiation. 1H NMR (400 MHz,

CDCl3), δ (TMS, ppm): 3.92 (t, 2H, CH2OH), 4.0 (t, 2H, OCH2CH2), 6.64 (d, 2H,

ArH), 6.94 (d, 2H, ArH), 6.987.06 (m, 6H, ArH), 7.087.12 (m, 9H, ArH). The

1H NMR spectrum agreed with literature data.2, 3

References

1 C. A. Harper, Handbook of Plastics, Elastomers & Composites, The McGraw-Hill

Companies, Inc., 2002.

2 G. D. Liang, L. T. Weng, J. W. Y. Lam, W. Qin and B. Tang, Acs Macro Lett., 2014,

3, .

3 G. D. Liang, J. W. Y. Lam, W. Qin, J. Li, N. Xie and B. Z. Tang, Chem. Commun.,

2014, 50, .