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finally, diethyl ether was eliminated in vacuo. The crude product
was purified by column chromatography [silica gel; petroleum
ether/diethyl ether (3:1) as an eluent]. The light yellow liquid
product 1 (14.9 g) was obtained by vacuum distillation method
extinction coefficient [37]. Next, ZnS shells were deposited in a
layer-by-layer fashion via the SILAR method [38]. In a typical syn-
thesis of CdSe/ZnS coreeshell NCs, 3 mL of ODE and 0.1 g of ODA
were loaded into a 50 mL reaction flask, the purified CdSe NCs in
hexanes were added, and the system was kept at 100 ꢀC under
nitrogen flow for 30 min to remove hexanes with low vapor pres-
sure. Subsequently, the solution was heated to 220 ꢀC for the shell
growth. The sulfur precursor and zinc precursor were injected
sequentially, allowing a minimum of 10 min between injections to
allow for shell annealing. The process was repeated until a desired
thickness was grown.
(78% yield). 1H NMR (500 MHz, CDCl3,
d): 6.84 (s, 4H, aromatic H),
3.8 (s, 2H, eOCH2e), 3.78 (s, 3H, eOCH3), 0.9e1.7 (m, 15H).
2.3. Synthesis of 1,4-bis(chloromethyl)-5-(2-ethylhexyloxy)-2-methoxy-
benzene (2) [33,34]
Compound 2 was synthesized by reacting compound 1 (10 g,
43 mmol) with of formaldehyde (20 g, 0.67 mol) and concentrated
hydrochloric acid (40 mL) in of 1,4-dioxane (30 mL). After the solu-
tion was heated at 90 ꢀC for 3 days, the ethyl acetate and water were
added into the reaction mixture when it cooled to ambient tem-
perature. After the precipitation was filtrated, the crude solid was
dissolved in a small amount of hot cyclohexane and then poured the
solution into ice-cold methanol. The white solid was obtained after
filtration and vacuum drying (6.06 g, 43% yield, mp 47e48 ꢀC). 1H
2.8. Preparation of polymer bulk nanocomposites
The CdSe/ZnS NCs, S-1.5 and MQ were dispersed in monomer
mixtures of DMAA, St and DVB. The weight ration of DMAA/St/DVB
was fixed to be 1:5:0.3. Subsequently, 3% w/w of AIBN was added to
the above transparent dispersion, and the pre-polymerization was
carried out at 75 ꢀC for 15 min after degassing. Then, the poly-
merization systems were cured at 45 ꢀC for 12 h, followed by a
programmed heating process from 50 to 110 ꢀC (at 10 ꢀC/h) and
then held at 120 ꢀC for 3 h. Finally, a series of transparent nano-
composites were obtained. The polymer bulk materials with CdSe/
ZnS NCs or S-1.5 were defined as P-QD and P-PPV, respectively.
Polymer bulk materials containing CdSe/ZnS NCs and S-1.5 (1:1, w/
w) were simply defined as P-NCs-PPV. The synthetic recipes of P-
NCs/MQ-PPV with different dosages of CdSe/ZnS NCs, S-1.5 and MQ
were shown in Table S1.
NMR (500 MHz, CDCl3, d): 6.92 (d, 2H, aromatic H), 4.64 (s, 4H, e
CH2Cl), 3.88 (d, 2H, eOCH2e), 3.86 (s, 3H, eOCH3), 0.9e1.75 (m,15H).
2.4. Synthesis of S-(4-vinyl)-benzyl isothiourea hydrochloride
(SVBTC) [35]
15.3 g of 4-vinylbenzyl chloride (0.1 mol), 9.12 g of thiourea
(0.12 mol), 200 mL of ethanol and 0.08 g of 4-methyloxyphenol as
inhibitor were put into a three-necked flask fitted with a reflux
condenser. The reaction mixture was stirred at reflux temperature for
4 h under N2 flow. Then the resulting solution cooled to ambient
temperature and was concentrated at a reduced pressure. The sur-
vival was poured into a large amount of diethyl ether and the white
precipitate was collected and thoroughly washed several times with
2.9. Characterization
FTIR spectra were recorded on a Magna 560 FT-IR spectrometer.
NMR spectra were obtained from an AVANCE Bruker spectrometer
at basic frequencies of 500 MHz for 1H and 125 MHz for 13C in CDCl3
solution. UVevis absorption spectra were recorded on a Vary 500
UVeviseNIR spectrometer in the range 200e800 nm. The photo-
luminescence properties were measured on a Cary 500 fluores-
cence spectrometer. The molecular weights of polymers were
estimated at a flow rate of 1.0 mL minꢁ1 at 25 ꢀC by gel permeation
chromatography (GPC) on a Waters instrument (Waters Corpora-
tion, USA), using CHCl3 as eluent, and the molecular weights were
determined vs polystyrene standards. X-ray diffraction (XRD) pat-
terns were measured using a Rigaku D/max-IIB X-ray diffractom-
diethyl ether, and then dried in vacuum. 1H NMR (500 MHz, D2O,
d):
7.30 (d, 2H, aromatic H), 7.23 (d, 2H, aromatic H), 6.57 (q, 1H, eCH]),
5.67 (d, 1H, ]CH2), 5.13 (d, 1H, ]CH2), 4.19 (s, 2H, eCH2Se).
2.5. Synthesis of MEH-PPV
To a round-bottom flask were added 3.5 g of tert-BuOK, 20 mL of
dry 1,4-dioxane. Under N2 atmosphere, a solution of compound 2
(1.0 g) in dry 1,4-dioxane (10 mL) was dropped into the above flask.
During this procedure, the solution gradually turned from colorless
to orange. The reaction mixture was stirred at 60 ꢀC for 4 h, then
cooled to room temperature and poured into a large amount of
methanol. Further purification was effected by re-precipitation
from CHCl3/MeOH and dried in vacuo.
eter at a scanning rate of 6ꢀ minꢁ1 with 2
q
ranging from 5ꢀ to 80ꢀ,
ꢀ
using CuK
a
radiation (
l
¼ 1.5418 A). Transmission electron micro-
scopy (TEM) was carried out on a JEM-2100F microscope. Ther-
mogravimetric analysis (TGA) was performed on a Perkin Elmer
TGA-2 thermogravimetriꢁc1 analyzer under air atmosphere at a
2.6. Synthesis of the novel polymers
heating rate of 10 ꢀC min
.
Under N2 atmosphere and vigorous stirring, a solution of com-
pound 2 (1.0 g) in dry 1,4-dioxane (10 mL) was dropped into a solution
of tert-BuOK (3.5 g), and varying weight of SVBTC in dry 1,4-dioxane
(20 mL). The reaction temperature was maintained at 60 ꢀC for 4 h
and then cooled to room temperature. The precipitate was collected
after pouring the reaction solution into a large amount of methanol. It
was further purified by re-precipitating from CHCl3/MeOH and dried
in vacuo. By using 0.65 g or 0.975 g of SVBTC, two kinds of novel
polymers defined as S-1 or S-1.5 can obtained, respectively.
3. Results and discussion
3.1. Synthesis and characterization of novel polymers
The preparation process of the novel polymer is illustrated in
Scheme 1. The polymerization reaction occurs between compound
2 and SVBTC in the presence of tert-BuOK via p-quinodimethane
intermediate as the actual monomer. The SeC bond of SVBTC is
polarized under the strongly basic conditions and it attacks the
active intermediate and induces the polymerization reaction of PPV
and eventually generates the novel polymer with the styrene group
and carboxyl group in the side chains. The PPV and PPX units are
possibly randomly arranged in the main chain of the polymers. The
obtained polymers have excellent solubility in CHCl3 and THF.
The color of the polymers gradually becomes lighter from red to
2.7. Synthesis of the CdSe/ZnS coreeshell NCs
The CdSe core was synthesized following traditional methods by
using oleic acid (OA) as the capping agents [36]. The concentration
of the CdSe QD core was then calculated using the size dependent