Electronic supplementary information (ESI)
for
A Novel Method for Preparing Silver/Poly(siloxane-b-methyl
methacrylate) Nanocomposites with Multiple Properties in the
DMF-Toluene Mixture Solvent
Hua Chengb, Yin-Ning Zhoua, Zheng-Hong Luoa, b*
a
Department of Chemical Engineering, School of Chemistry and Chemical
Engineering, Shanghai Jiao Tong University, Shanghai 200240, P R China
b
Department of Chemical and Biochemical Engineering, College of Chemistry and
Chemical Engineering, Xiamen University, Xiamen 361005, P R China
* Correspondence to: Z.H. Luo; e-mail: luozh@sjtu.edu.cn
Tel.: +86-21-54745602
Fax: +86-21-54745602
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Experimental
Materials
Monocarbinol-terminated polydimethylsiloxane (PDMS-OH, 5000 g/mol) and
Ethyl 2-bromoisobutyrate (Eib-Br, 98%) and 2-bromo-2-methyl-propionylbromide
(98%) were obtained from A Better Choice for Research Chemicals GmbH & Co. KG
(ABCR, Germany). Triethylamine(99%) was supplied by Sinopharm Chemical
Reagent Co, Ltd. (SCRC，China) and stored over 4-Å molecular sieves. Methyl
methacrylate (MMA, CP) was purchased from SCRC and was washed with 5 wt. %
aqueous
NaOH
solution
to
remove
the
inhibitor.
1,1,4,7,7-pentamethyl
diethylenetriamine (PMDETA, 98%), tryptone, yeast powder as well as agar were of
analytical grade and used without further purification which were obtained from
Sigma-Aldrich, USA. Cu (I) Br (98%) was supplied by SCRC and was purified by
glacial acetic acid and methanol. Dimethyl formamide (DMF, 99%), silver nitrate
(AgNO3, AR) and all other reagents and solvents were of analytical grades which
were obtained from SCRC and used without further purification.
Measurement methods
Proton nuclear magnetic resonance (1H NMR) of PDMS-b-PMMA was recorded
on a Bruker AV400 instrument with deuterated chloroform as the solvent.
The molecular weight (Mn) and molecular weight distribution (Mw/Mn, PDI) of
the cleaved polymers of PDMS-Br and PDMS-b-PMMA were determined at 40 °C by
gel permeation chromatography (GPC) equipped with a waters 1515 isocratic HPLC
pump, three Styragel columns (Waters HT4, HT5E, and HT6) and a waters 2414
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refractive index detector (set at 30 °C), using THF as the eluent at the flow rate of
1.0mL min-1. A series of polystyrene narrow standards were employed to generate a
universal calibration curve.
X-ray photoelectron spectroscopy (XPS) spectra were recorded in order to
determine the surface composition of Ag/PDMS-b-PMMA nanoparticles using a PHI
quantum 2000 scanning ESCA microprobe (physical electronic, USA), equipped with
an Al Kα1, 2 monochromatic source of 1486.60 eV.
The formation of AgNPs was monitored by observing the surface plasmon
resonance of the AgNPs using a UV-visible spectrophotometer (UV-2550).
Transmission electron micrographs (TEM) were obtained on a transmission
electron microscope (JEM-2100) operated at an accelerating voltage at 200 kV.
SEM images were obtained from a field emission scanning electron microscope
(LEO1530), equipped with a setup for element analysis by X-ray energy
dispersion(EDX). Sample preparation for SEM was performed by dropping the
reaction solution on clean silicon wafer. After air-drying for 3 h at room temperature,
the samples were treated by gold sputtering.
The thermol property was recorded on SDTQ600 thermo gravimetric analyzer and
set the measurable temperature range from room temperature to 800 ℃ in nitrogen
atmosphere while fixing the heating rate at 10 ℃/min.
Static water contact angles of the nanocomposites films were measured by casting
the 2 wt% THF nanocomposite solutions on glass slides and were recorded on a
telescopic goniometer (DSA30) contact angle measurements. The reduction rate of
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the silver ions was characterized on Atomic Absorption Spectrophotometer
(TAS-986), while keep the acetylene flow rate at 1.3-1.4 L/min and set the
wavelength at 328.1 nm.
Preparation of PDMS-b-PMMA with different block lengths
PMMA was synthesized by atom transfer radical polymerization (ATRP) in this
work. The typical molar ratio of [CuBr]/[PMDETA]/[Eib-Br]/[MMA] was 1:1:1:100,
(yield: 65%). The 1H NMR and GPC were shown in Figure S1-2. PDMS-b-PMMA
block copolymers were prepared by ATRP as our contemporaneous work showed in
Scheme S1-2.1 Different lengths of PMMA block were synthesized with
[MMA]/[I]=20/1, 50/1, 80/1, and 100/1. The four kinds of copolymer were obtained
and their chemical structures are shown in the 1H NMR spectrum. As shown in
Figure S3, a distinct peak at 3.70 ppm belongs to -OCH3, which indicated the
copolymerization of MMA with PDMS. Herein, the PDMS block has distinctive peak
centered at 0.15 ppm, corresponding to the dimethylsiloxane repeat units. Integal
ratios of the dimethylsiloxane repeat units at 0.15 ppm to the region at 3.70 ppm could
be used to calculate the absolute number-average molecular weight value. In addition,
Figure S4 describes the number-average molecular weight (Mn,GPC) and molecular
weight distribution (PDI) of the resulting macroinitiator and copolymers. The elution
peaks are symmetric and exhibits few tailing at the lower molecular weight side with
narrow molecular weight distribution of the resulting copolymers. For comparison,
the number of monomer units agreed quite well with the NMR results. The ultimately
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chemical compositions of the resultant products are composed of PDMS65-b-PMMA8,
PDMS65-b-PMMA18, PDMS65-b-PMMA30 and PDMS65-b-PMMA67, respectively.
Figure S1. 1H NMR spectrum of the PMMA polymer in CDCl3.
Figure S2. GPC traces of the PMMA polymer.
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Scheme S1. Synthetic Scheme of the PDMS-Br Macroinitiator.
Scheme S2. Synthetic Scheme of the PDMS-b-PMMA Diblock Copolymers.
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Figure S3. 1H NMR spectrum of the PDMS-b-MMA diblock copolymers in CDCl3.
(A) PDMS65-b-PMMA8; (B) PDMS65-b-PMMA18; (C) PDMS65-b-PMMA30; (D)
PDMS65-b-PMMA67.
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Figure S4. GPC traces of the PDMS-Br and PDMS-b-MMA diblock copolymers.
(from
right
to
left)
PDMS-Br,
PDMS65-b-PMMA8,
PDMS65-b-PMMA18,
PDMS65-b-PMMA30, PDMS65-b-PMMA67.
Literature Cited
1. Yu L, Qiu JJ, Cheng H, Luo ZH. Facile preparation of gold nanoparticles using
the self-assembled ABC non-amphiphilic fluorosilicone triblock copolymer
template. Mater Chem Phys. 2013;138:780-786.
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