354
Femández, & Benito, 2011; Yan et al., 2010; Yuan, Zou, Guo, Wang,
& Ren, 2012). Some polymers with the structure of -CD moiety
have been found that they have the potential to remove toxic com-
& Shuter, 2010; Pan, Du, Zhao, & Xu, 2012; Xiong et al., 2012; Yuan,
Yuan, Zhou, Wu, & Hong, 2010). MNPs can also be used as removal
metals or oxide, and surfactants have been reported in the elim-
ination of microcystins, heavy metal ions, and dyes in water (Chen,
Zhang, Chen, Zhang, & Zhang, 2010; Dai & Nelson, 2010; Deng,
Qi, Deng, Zhang, & Zhao, 2008; Vollath, 2010; Zhou, Gao, & Xu,
2010). However, the procedures of preparing magnetic adsorbents
via surface-modification are comparatively complicated and ineffi-
cient because the magnetic nanoparticles should be modified to be
used as the initiator to initiate the polymerization and prepare the
Polyhedral oligomeric silsesquioxane (POSS) is a class of unique
inorganic component that can be incorporated into polymer matrix
to produce novel hybrid polymers with advantageous properties
(Li, Chung, & Kuo, 2012; Tanaka & Chujo, 2012). Among them,
each of the eight corners carries one organic group. The corner
group is reactive so it can be used as initiating centers to prepare
star-shaped inorganic–organic polymeric materials (Fan, Wang, &
Zheng, 2010; Wu & Kuo, 2012; Ye et al., 2012).
In this paper, we have reported the synthesis of a novel
amphiphilic star-shaped inorganic–organic hybrid copolymer
polyhedral oligomeric silsesquioxane-poly (-caprolactone)--
cyclodextrin (POSS-PCL--CD) by ring-opening polymerization
(ROP) and click chemistry, as shown in Scheme 1. 1H NMR
suggested that the copolymer was synthesized successfully. The
hybrid micelles based on the complex of Fe3O4 nanoparticles
were conveniently prepared by mixing POSS-PCL--CD with Fe3O4
nanoparticles in solvent and dialysis against water. TEM images
showed that Fe3O4 nanoparticles were encapsulated into the
micelle core consisting of hydrophobic POSS and biodegradable PCL
segments. The micelle shell was consisting of mono-functionalized
-CDs. Due to the host–guest interaction of -CD with BPA, the
magnetic hybrid micelles would be used as adsorbents to remove
BPA in water (of course, it is a limitation for this micelle system to
remove other compounds in polluted water) and then can be easily
separated by an external magnetic field, the adsorption behavior
of BPA was investigated using UV spectra. The magnetic hybrid
micelles have potential application in the field of environmental
protection especially in the treatment of polluted water.
Biochem, Shanghai), 4-dimethylaminopyridine (DMAP; Fluka,
USA), N,N,Nꢀ,Nꢀ,Nꢀꢀ-pentamethyldiethylenetriamine (PMDETA,
Acros Organic), silver nitrate (AgNO3; Acros Organic), sodium
hydroxide (NaOH; Shanghai Chemical Reagent Co., China), iron
acetylacetonate (Fe(acac)3; Acros Organic), 1,2-dodecanediol
(Aldrich, 90%), oleylamine (Aldrich, 70%), and oleic acid (Aldrich,
90%) were used as received. CuBr was recrystallized and dried
to the literature (Brady, Lynam, O’Sullivan, Ahern, & Darcy, 2000;
Muderawan et al., 2005). Propargyl 3-carboxylic-propanoate was
synthesized according to our previous work (Yuan, Zhao, Gu, & Ren,
2.2. Characterization
Nuclear magnetic resonance (NMR). NMR spectra of samples
were obtained from
a Bruker DMX 500 NMR spectrometer
using CDCl3 as solvent. The chemical shifts were relative to
tetramethylsilane.
Gel permeation chromatography (GPC). The molecular weight and
molecular weight distribution were measured on a Viscotek TDA
302 gel permeation chromatography equipped with two columns
(GMHHR-H, M Mixed Bed). THF was used as eluent at a flow rate of
1 mL min−1 at 30 ◦C.
Dynamic light scattering spectrophotometer (DLS). The hydro-
dynamic radius (Rh) of copolymer micelles was investigated using
a scattering angle 90◦. The Rh was obtained by a cumulant
analysis.
Transmission electron micrographs (TEM). The morphology of
nano-assemblies was observed with a JEOL JEM-2010 TEM at an
accelerating voltage of 120 kV. The samples for TEM observation
were prepared by placing 10 L of nano-assemblies solution on
copper grids coated with thin films and carbon. The samples were
stained by 1% phosphotungstic acid.
Thermogravimetric analysis (TGA). TGA was carried on
a
TGA 2050 thermogravimetric analyzer with a heating rate of
20 ◦C min−1 from 20 ◦C to 800 ◦C under nitrogen atmosphere.
Magnetic sample magnetometry (VSM). Magnetic measurements
were performed on Lakeshore 7307 Vibrating Sample Magnetome-
ter system at room temperature.
Ultraviolet–vis spectroscopy (UV–vis). UV–vis spectroscopy
measurements were performed on a UV 2100 UV–vis Spectropho-
tometer (SHIMADZU, Japan).
2.3. Synthesis of Fe3O4 nanoparticles
Fe(acac)3 (706 mg, 2 mmol), 1,2-dodecanediol (2.023 g,
10 mmol), oleic acid (1.695 g, 6 mmol), oleylamine (1.605 g,
6 mmol), and diphenyl ether (20 mL) were mixed and magnetically
stirred under a flow of argon. The mixture was heated to 200 ◦C
for 30 min and then heated to 280 ◦C for another 30 min. The
black–brown mixture was cooled to room temperature under
argon atmosphere. A black material was precipitated with ethanol
and separated via centrifugation. The black product was dissolved
in hexane, precipitated with ethanol, centrifuged to remove the
solvent, and dispersed into hexane. Fe3O4 nanoparticles were
obtained after evaporation of hexane at room temperature (yield:
31%).
2. Materials and methods
2.1. Materials
3-Chloropropyltrimethoxysilane (Acros Organic, USA), sodium
azide (NaN3, Alfa Aesar), dicyclohexylcarbodiimide (DCC; GL