Structure and Properties of Polyaniline Micro- and Nano …
509
The purpose of the work was to study the influence of the nature of the noble
metal (Ag, Au, Pt, Pd) on the patterns of synthesis and structure of composites
with polyaniline (PAn) obtained by one-step synthesis in the conditions of emulsion
polymerization.
2 Experimental
2.1 Synthesis of Composites
For the synthesis of metal-containing composites, the method of microemulsion
polymerization [24] was chosen, which was realized by the next procedure. 0.64 g
of Na 2 S 2 O 8 , 3 ml of butyl alcohol C 4 H 9 OH, 40 ml of hexane C 6 H 14 were added to
the solution containing 4.5 g of sodium dodecyl sulfate C 12 H 25 SO 4 Na in 15 ml of
1 M H 2 SO 4 and stirred for about 20 min to a homogeneous state. After that, 0.5 ml
of distilled aniline was added dropwise with stirring and the calculated amount of
a solution of the metal compound (HAuCl 4 /H 2 PtCl 6 /K 2 PdCl 4 /AgNO 3 ) to achieve a
metal content of 15% by weight of the composite. The reaction was carried out with
constant stirring at room temperature for 24 h. The precipitate was separated, washed
by water and acetone, and dried at 80 °C to constant mass according to traditional
procedure [11, 12]. Samples obtained by microemulsion polymerization at the ratio
of oxidant: monomer = 1:2 became the basis for the synthesis of four composites
of polyaniline-metal: PAn-gold, PAn-platinum, PAn-palladium, PAn-silver in 1 M
H 2 SO 4 organic-water solution. All reagents and materials used were of high quality,
purchased from Sigma-Aldrich. The metal content was selected on the basis of literature data and previous experiments, since with smaller quantities of metal it does
not have a significant effect on the properties of the composite, and at larger metal
aggregation into clusters occurs.
2.2 Methods
Powder specimens were prepared for X-ray studies by careful grinding in an agate
mortar of polyaniline or its composites. The powder of the sample was deposited
in a uniform layer to a special amorphous film for X-ray experiments and was
fixed with another film in the cuvette. The arrays of experimental intensities and
reflected angles from the samples were obtained using an automatic STOE STADI P
diffractometer (manufactured by STOE & Cie GmbH, Germany) with a PSD linear
positional precision detector according to the modified Guignet geometry (CuKα 1 -
radiation); concave Ge-monochromator (111) of Johann type; 2θ /ω-scanning, the
interval of angles 2ϑ 0.500 ≤ 2θ ≤ 120.185 °2θ with step 0.015 °2θ. Initial processing
of experimental diffraction arrays, calculation of theoretical diffraction patterns of
509
The purpose of the work was to study the influence of the nature of the noble
metal (Ag, Au, Pt, Pd) on the patterns of synthesis and structure of composites
with polyaniline (PAn) obtained by one-step synthesis in the conditions of emulsion
polymerization.
2 Experimental
2.1 Synthesis of Composites
For the synthesis of metal-containing composites, the method of microemulsion
polymerization [24] was chosen, which was realized by the next procedure. 0.64 g
of Na 2 S 2 O 8 , 3 ml of butyl alcohol C 4 H 9 OH, 40 ml of hexane C 6 H 14 were added to
the solution containing 4.5 g of sodium dodecyl sulfate C 12 H 25 SO 4 Na in 15 ml of
1 M H 2 SO 4 and stirred for about 20 min to a homogeneous state. After that, 0.5 ml
of distilled aniline was added dropwise with stirring and the calculated amount of
a solution of the metal compound (HAuCl 4 /H 2 PtCl 6 /K 2 PdCl 4 /AgNO 3 ) to achieve a
metal content of 15% by weight of the composite. The reaction was carried out with
constant stirring at room temperature for 24 h. The precipitate was separated, washed
by water and acetone, and dried at 80 °C to constant mass according to traditional
procedure [11, 12]. Samples obtained by microemulsion polymerization at the ratio
of oxidant: monomer = 1:2 became the basis for the synthesis of four composites
of polyaniline-metal: PAn-gold, PAn-platinum, PAn-palladium, PAn-silver in 1 M
H 2 SO 4 organic-water solution. All reagents and materials used were of high quality,
purchased from Sigma-Aldrich. The metal content was selected on the basis of literature data and previous experiments, since with smaller quantities of metal it does
not have a significant effect on the properties of the composite, and at larger metal
aggregation into clusters occurs.
2.2 Methods
Powder specimens were prepared for X-ray studies by careful grinding in an agate
mortar of polyaniline or its composites. The powder of the sample was deposited
in a uniform layer to a special amorphous film for X-ray experiments and was
fixed with another film in the cuvette. The arrays of experimental intensities and
reflected angles from the samples were obtained using an automatic STOE STADI P
diffractometer (manufactured by STOE & Cie GmbH, Germany) with a PSD linear
positional precision detector according to the modified Guignet geometry (CuKα 1 -
radiation); concave Ge-monochromator (111) of Johann type; 2θ /ω-scanning, the
interval of angles 2ϑ 0.500 ≤ 2θ ≤ 120.185 °2θ with step 0.015 °2θ. Initial processing
of experimental diffraction arrays, calculation of theoretical diffraction patterns of