NPs (Fig. 19a) and 1.16 A ˚ and 2.00 A ˚ for nickel NPs (Fig. 19b) [81]. This suggests
only the short order of metal atoms and demonstrates the amorphous character of
the NPs. In the case of larger NPs, distinct reflections of metal lattices (Fig. 19c,d)
(copper, nickel, or silver) are clearly observed [115, 132, 133].
Since metal NPs act as active filler in the IPEC {PAA-PEI} matrix, their
formation leads to the immobilization of carboxylate groups on their positively
charged surfaces [115]. A high radiation–chemical yield for the reduction of metal
ions [81, 114, 115, 132, 133] embedded into the IPEC matrices can be used for the
development of single-stage methods for preparation of nanocomposites, applying
various types of ionization radiation.
In general, one may conclude that both chemical and radiation–chemical
approaches provide effective reduction of metal ions directly in IPEC matrices.
This leads to the formation of stabilized NPs. However, it was found that the chemical
method is applicable only for a preparation of NPs in thermally crosslinked IPECs.
Apparently, a poor regularity of the chemical processes causes noncrosslinked
matrices to disintegrate. In contrast, the irradiation technique allows one to derive
nanocomposites from both crosslinked and noncrosslinked IPEC films due to specific
control over the radiation-induced processes.
4.3 Advanced Structures Based on Metallo-Containing IPECs
A controlled macromolecular assembly in solution is a universally exploited way for
preparation of materials for nanotechnology. In particular, the LbL technology has
been applied to the fabrication of coated core–shell particles and hollow capsules
[103, 135, 136]. The fabricated core–shell and hollow particles may be used for
various applications in catalysis, optics, drug delivery, and biosensing. They can
serve as precursors for polymer–metal nanohybrids [103]. Reduction reactions are
usually used for preparation of metal NPs inside of such multilayered polyelectrolyte
systems. Specifically, polyelectrolytes whose charged groups are coordinated with
metal ions may act as one of the components in the LbL systems. Alternatively, the
sorption of metal ions from a solution leads to incorporation of metal ions into
core–shell particles and hollow capsules [137]. Hollow capsules composed of PSSdoped polyaniline and PAH with bound Ag
þ were used for a preparation of capsules
containing silver [138]. In this case, the PSS-doped polyaniline acts as reducing agent
for Ag
þ
. Laser scanning during confocal microscope imaging can accelerate the
reduction (Fig. 21a).
Micrometer-sized hollow spheres with metal NPs (10–30 nm) were obtained
by photoreduction of Ag
þ in polyelectrolyte multilayers comprising Ag
þ -PSS
layers immobilized onto submicrometer-sized PS particles [138]. Hollow capsules
with metal NPs can be formed either via a reduction of Ag
þ followed by a core
dissolution or by a core dissolution with a subsequent reduction of Ag
þ . The
formed spherical nanocomposites with silver NPs were stable for long time
(over 3 months). The silver-based core–shell particles and hollow spheres may
find interesting applications in catalysis and molecular photoprinting. The PEI-Pd
2+
Advanced Functional Structures Based on Interpolyelectrolyte Complexes
213
only the short order of metal atoms and demonstrates the amorphous character of
the NPs. In the case of larger NPs, distinct reflections of metal lattices (Fig. 19c,d)
(copper, nickel, or silver) are clearly observed [115, 132, 133].
Since metal NPs act as active filler in the IPEC {PAA-PEI} matrix, their
formation leads to the immobilization of carboxylate groups on their positively
charged surfaces [115]. A high radiation–chemical yield for the reduction of metal
ions [81, 114, 115, 132, 133] embedded into the IPEC matrices can be used for the
development of single-stage methods for preparation of nanocomposites, applying
various types of ionization radiation.
In general, one may conclude that both chemical and radiation–chemical
approaches provide effective reduction of metal ions directly in IPEC matrices.
This leads to the formation of stabilized NPs. However, it was found that the chemical
method is applicable only for a preparation of NPs in thermally crosslinked IPECs.
Apparently, a poor regularity of the chemical processes causes noncrosslinked
matrices to disintegrate. In contrast, the irradiation technique allows one to derive
nanocomposites from both crosslinked and noncrosslinked IPEC films due to specific
control over the radiation-induced processes.
4.3 Advanced Structures Based on Metallo-Containing IPECs
A controlled macromolecular assembly in solution is a universally exploited way for
preparation of materials for nanotechnology. In particular, the LbL technology has
been applied to the fabrication of coated core–shell particles and hollow capsules
[103, 135, 136]. The fabricated core–shell and hollow particles may be used for
various applications in catalysis, optics, drug delivery, and biosensing. They can
serve as precursors for polymer–metal nanohybrids [103]. Reduction reactions are
usually used for preparation of metal NPs inside of such multilayered polyelectrolyte
systems. Specifically, polyelectrolytes whose charged groups are coordinated with
metal ions may act as one of the components in the LbL systems. Alternatively, the
sorption of metal ions from a solution leads to incorporation of metal ions into
core–shell particles and hollow capsules [137]. Hollow capsules composed of PSSdoped polyaniline and PAH with bound Ag
þ were used for a preparation of capsules
containing silver [138]. In this case, the PSS-doped polyaniline acts as reducing agent
for Ag
þ
. Laser scanning during confocal microscope imaging can accelerate the
reduction (Fig. 21a).
Micrometer-sized hollow spheres with metal NPs (10–30 nm) were obtained
by photoreduction of Ag
þ in polyelectrolyte multilayers comprising Ag
þ -PSS
layers immobilized onto submicrometer-sized PS particles [138]. Hollow capsules
with metal NPs can be formed either via a reduction of Ag
þ followed by a core
dissolution or by a core dissolution with a subsequent reduction of Ag
þ . The
formed spherical nanocomposites with silver NPs were stable for long time
(over 3 months). The silver-based core–shell particles and hollow spheres may
find interesting applications in catalysis and molecular photoprinting. The PEI-Pd
2+
Advanced Functional Structures Based on Interpolyelectrolyte Complexes
213