3 Structural Peculiarities and Properties of Silver-Containing Polymer. . .
59
Fig. 3.6 Wide-angle X-ray
diffractograms of (1) the
IPEC, (2) the IMC, and (3–5)
the IPEC–Ag nanocomposites
obtained via the chemical
reduction of Ag + ions in the
IMC at molar ratios of
BH 4
− :Ag + = (3) 1.0, (4) 2.0,
and (5) 3.0
10
20
30
40
50
0
10
20
5
4
(200)
(111)
3
2
1
~
I, rel. units.
2q, deg
the appearance of an intense diffuse diffraction maximum at 2θ m ∼ 11.2 ◦ , featuring
the structure polyelectrolyte–metal complex pectin–Ag + –PEI [18] (curve 2). In
its turn, the amorphous halo disappears at 2θ m ∼ 20.8 ◦ , relating to the structural
peculiarity of pectin–PEI IPEC. This indicates the full transfer of polyelectrolyte
complexes into polyelectrolyte–metal complexes.
After the chemical reduction of the Ag + ions in the IMC with the use of sodium
borohydride (a molar ratio of [BH 4
− ]:[Ag + ] = 1.0) a nanocomposite based on
the IPEC and Ag was formed. In the diffractogram of IPEC–Ag nanocomposite
(curve 3), the diffraction maximum at 2θ m ∼ 11.2 ◦ , which is typical of the
abovementioned polyelectrolyte–metal complexes, is absent, unlike the two intense
maxima at 2θ m = 38.2 ◦ and 43.8, corresponding to the crystallographic plan of the
face-centered cubic lattice of silver with (111) and (200) indexes, respectively, and
confirming presence of metal silver in the polymeric system.
With an increase in the amount of the reducing agent (a molar ratio of
[BH 4
− ]:[Ag + ] = 2.0), the X-ray diffractograms of nanocomposites based on the
IPEC and Ag (curves 4) show a significant increase in the intensity of the diffraction
peaks at 2θ m = 38.2 ◦ and 43.8 ◦ , characterizing the structure Ag nanoparticles. The
increase in the amount of the reducing agent (a molar ratio of [BH 4
− ]:[Ag + ] = 3.0)
does not change the structuring of the nanocomposites based on the IPEC and Ag
nanoparticles (curves 4, 5).
Thus, according to wide-angle X-ray diffraction, it may be concluded that
the molar ratio [BH 4
− ]:[Ag + ] = 2.0 is optimum for the formation of IPEC–Ag
nanocomposites.
Analysis of diffractograms of silver-containing nanocomposites prepared by
thermal reduction of Ag + ions in IMC in the wide range of temperatures (100–
160 ◦ ´) has shown, while the gradual increase of the temperature to µ = 150 ◦ ´ is
59
Fig. 3.6 Wide-angle X-ray
diffractograms of (1) the
IPEC, (2) the IMC, and (3–5)
the IPEC–Ag nanocomposites
obtained via the chemical
reduction of Ag + ions in the
IMC at molar ratios of
BH 4
− :Ag + = (3) 1.0, (4) 2.0,
and (5) 3.0
10
20
30
40
50
0
10
20
5
4
(200)
(111)
3
2
1
~
I, rel. units.
2q, deg
the appearance of an intense diffuse diffraction maximum at 2θ m ∼ 11.2 ◦ , featuring
the structure polyelectrolyte–metal complex pectin–Ag + –PEI [18] (curve 2). In
its turn, the amorphous halo disappears at 2θ m ∼ 20.8 ◦ , relating to the structural
peculiarity of pectin–PEI IPEC. This indicates the full transfer of polyelectrolyte
complexes into polyelectrolyte–metal complexes.
After the chemical reduction of the Ag + ions in the IMC with the use of sodium
borohydride (a molar ratio of [BH 4
− ]:[Ag + ] = 1.0) a nanocomposite based on
the IPEC and Ag was formed. In the diffractogram of IPEC–Ag nanocomposite
(curve 3), the diffraction maximum at 2θ m ∼ 11.2 ◦ , which is typical of the
abovementioned polyelectrolyte–metal complexes, is absent, unlike the two intense
maxima at 2θ m = 38.2 ◦ and 43.8, corresponding to the crystallographic plan of the
face-centered cubic lattice of silver with (111) and (200) indexes, respectively, and
confirming presence of metal silver in the polymeric system.
With an increase in the amount of the reducing agent (a molar ratio of
[BH 4
− ]:[Ag + ] = 2.0), the X-ray diffractograms of nanocomposites based on the
IPEC and Ag (curves 4) show a significant increase in the intensity of the diffraction
peaks at 2θ m = 38.2 ◦ and 43.8 ◦ , characterizing the structure Ag nanoparticles. The
increase in the amount of the reducing agent (a molar ratio of [BH 4
− ]:[Ag + ] = 3.0)
does not change the structuring of the nanocomposites based on the IPEC and Ag
nanoparticles (curves 4, 5).
Thus, according to wide-angle X-ray diffraction, it may be concluded that
the molar ratio [BH 4
− ]:[Ag + ] = 2.0 is optimum for the formation of IPEC–Ag
nanocomposites.
Analysis of diffractograms of silver-containing nanocomposites prepared by
thermal reduction of Ag + ions in IMC in the wide range of temperatures (100–
160 ◦ ´) has shown, while the gradual increase of the temperature to µ = 150 ◦ ´ is