Electronic Supplementary Material
Sterically Stabilized Polypyrrole-Palladium Nanocomposite Particles
Synthesized by Aqueous Chemical Oxidative Dispersion
Polymerization
Hiroyuki Hamasaki1, Nobuyuki Fukui1,Syuji Fujii1*, Shin-ichi Yusa2,
Yoshinobu Nakamura1
1
Department of Applied Chemistry, Faculty of Engineering
Osaka Institute of Technology, 5-16-1 Ohmiya, Asahi-ku, Osaka, 535-8585, Japan.
2
Graduate School of Engineering, University of Hyogo
2167, Shosha, Himeji, Hyogo 671-2280, Japan
Author to whom correspondence should be addressed (s.fujii@chem.oit.ac.jp).
Optical microscopy
A drop of the diluted PPy-Pd nanocomposite products was placed on a microscope slide
and observed using an optical microscope (Shimadzu Motic BA200) fitted with a digital
system (Shimadzu Moticam 2000).
Dynamic light scattering
Dynamic light scattering (DLS) measurements were carried out on a Malvern Zeta Sizer
Nano Series Nano-ZS instrument employing a 4.0 mW He-Ne laser (λ = 633 nm) at
25 °C.
Hydrodynamic diameters of poly(4-lithium styrene sulfonic acid)
(PLSSA)-stabilized PPy-Pd nanocomposite particle were larger than number-average
diameters determined using SEM images, which should be due to solvated PLSSA
colloidal stabilizer layer on the particle surface (see Table S1).
pH measurement
Before the polymerization, pH values of the PLSSA aqueous solution (300 wt% PLSSA
system) with dissolved pyrrole and PdCl2 aqueous solution were measured to be 4.2 and
2.4, respectively, using a pH meter (As One, CyberScan pH110): for recipe, see
experimental section in the manuscript. During the polymerization, pH drifted down
to pH 0.3: protons were released during the polymerization of pyrrole (see Scheme 1).
PPy-Pd, PPy, Pd and PLSSA loadings of PPy-Pd nanocomposite particles
PPy-Pd, PPy, Pd and PLSSA loadings of the PPy-Pd nanocomposite particles were
calculated using equations shown below.
PPy loading %=
Nitrogen content for PPy-Pd nanocomposite particles
×100 %
Nitrogen content for PPy bulk powder
PPy-Pd nanocomposite loading %
=
Nitrogen content for PPy-Pd nanocomposite particles
× 100 %
Nitrogen content for PPy-Pd bulk powder
Pd loading %=PPy-Pd nanocomposite loading % - PPy loading %
PLSSA loading %=100 % - PPy-Pd nanocomposite loading %
Table S1. Summary of hydrodynamic diameters of the PPy-Pd nanocomposite
particles dispersed in aqueous media.
Dza (nm)
a
PPy-Pd nanocomposite particles (PLSSA, 300 wt%b; 25 Cº c)
89
PPy-Pd nanocomposite particles (PLSSA, 400 wt%b; 25 Cº c)
89
PPy-Pd nanocomposite particles (PLSSA, 300 wt%b; 50 Cº c)
51
PPy-Pd nanocomposite particles (PLSSA, 300 wt%b; 75 Cº c)
121
Hydrodynamic diameter (Dz) measured by DLS
Weight percentage of PLSSA based on pyrrole monomer
c
Polymerization temperature
b
Table S2. Surface atomic compositions and Cl/N and S/N atomic ratios for PLSSA-stabilized PPy-Pd nanocomposite particles, PPy-Pd bulk
powder and PLSSA homopolymer as determined by XPS
Atom %
Atomic ratio
C
N
Pd
S
O
Cl
Li
Cl/N
S/N
PLSSA-stabilized
PPy-Pdnanocomposite particles
57.0
4.70
5.05
2.86
30.4
―
―
~0
0.61
PPy-Pd bulk powder
56.9
12.1
6.12
―
21.2
3.05
―
0.25
~0
PLSSA homopolymer
35.7
―
―
10.7
42.1
―
11.6
~0
~0
Figure S1 Optical microscope images of PPy-Pd nanocomposite particles synthesized
using various water soluble polymers as a colloidal stabilizer: PNVP, poly(N-vinyl
pyrrolidone);
PVA,
poly(vinyl
alcohol);
PAA,
poly(acrylic
acid);
PLSSA,
poly(4-lithium styrene sulfonic acid); PASSA, poly(4-ammonium styrene sulfonic acid)
Figure S2 Laser diffraction particle size distribution curves obtained for PPy-Pd
nanocomposite particles synthesized using various water soluble polymers as a colloidal
stabilizer: PNVP, poly(N-vinyl pyrrolidone); PVA, poly(vinyl alcohol); PAA,
poly(acrylic
acid);
PLSSA,
poly(4-lithium
styrene
sulfonic
acid);
PASSA,
poly(4-ammonium styrene sulfonic acid). Size distribution curve obtained for PPy-Pd
nanocomposite particles synthesized by precipitation polymerization in the absence of
any colloidal stabilizer is also shown.
PASSA also worked as an efficient colloidal
stabilizer and PPy-Pd nanocomposite particles with a volume-average diameter of 50±
20 nm were obtained.
Figure S3 Optical microscope images of PLSSA-stabilized PPy-Pd nanocomposite
particles synthesized at various PLSSA stabilizer concentrations: (a) 400, (b) 300, (c)
200, (d) 100, and (e) 0 wt% based on pyrrole monomer
Figure S4 SEM images of PLSSA-stabilized PPy-Pd nanocomposite particles
synthesized at various PLSSA stabilizer concentrations: (a) 400, (b) 300, (c) 200, (d)
100, and (e) 0 wt% based on pyrrole monomer
Figure S5 Laser diffraction particle size distribution curve obtained for PPy bulk
powder synthesized by precipitation polymerization in the absence of any colloidal
stabilizer
Figure S6 XPS spectra obtained for PPy-Pd nanocomposite particles (PLSSA 300
wt%), PPy-Pd nanocomposite bulk powder, and PLSSA homopolymer: core-level (a)
N 1s spectra, and (b) S 2p spectra