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.