outcome from three different laboratories. However, the three laboratories will
probably prepare the PEC sample by three different protocols and, of course, will
measure three different particle radii and distributions, probably using different
analytical methods and expertise. Hence, this section will not describe or propose
unified protocols for the reproducible analytical characterization and preparation of
PEC dispersions, but will give some experimental hints from selected experimentally oriented reports for consideration and critical discussion.
2.1 Characterization
Dynamic and static light scattering (DLS, SLS), scanning force microscopy (SFM),
scanning electron microscopy (SEM), and transmission electron microscopy
(TEM) are still the main methods for determining the size and shape of PEC
particles in solution or turbid dispersions. Therefore, a short summary on the history
of size and shape analysis of PEC nanoparticles, with a focus on light scattering and
microscopy, will be given.
2.1.1 Static Light Scattering
General experimental and theoretical principles and modalities on the SLS characterization of polydisperse particle systems can be found in the literature [24, 25]. To
the best of our knowledge, the group of Philipp and Dautzenberg were the first to
perform SLS studies on PEC dispersions. Comprehensive reviews on the approach
and modalities of applying SLS to PEC dispersions have been published [26, 27]. In
a related early article [28], Dautzenberg et al. reported SLS and viscosimetry results
on the influence of charge density and mixing ratio of PEC dispersions containing a
cationic copolymer of acrylamide and N-methyl-N,N-diethyl-N-ethylacrylate and
an anionic copolymer of acrylamide and acrylate (see Fig. 2).
2.1.2 Dynamic Light Scattering
General experimental and theoretical principles and modalities of DLS applied to
polydisperse particle systems can be found in the literature [24, 29]. The first DLS
work on PEC particles came to our knowledge from Dubin and Davis [30]
and Kabanov and Zezin [11]. Dubin and Murrell reported early DLS studies on
PEL/micelle complexes, including characterization of protein/PEL complexes
such as the BSA/PDADMAC system and its pH dependence by DLS [3] (see Fig. 3).
Kabanov and Zezin reported DLS studies on the complexation between synthetic
poly(N-dimethylaminoethylmethacrylate hydrochloride) (PDMAEMA) and
sodium polyphosphate and its dependence on the mixing ratio [11].
Recently, Lindhoud reported DLS titration studies on the reversibility and
relaxation behavior of PEC micelles composed of PDMAEMA, poly(acrylic
200
M. M€ uller
probably prepare the PEC sample by three different protocols and, of course, will
measure three different particle radii and distributions, probably using different
analytical methods and expertise. Hence, this section will not describe or propose
unified protocols for the reproducible analytical characterization and preparation of
PEC dispersions, but will give some experimental hints from selected experimentally oriented reports for consideration and critical discussion.
2.1 Characterization
Dynamic and static light scattering (DLS, SLS), scanning force microscopy (SFM),
scanning electron microscopy (SEM), and transmission electron microscopy
(TEM) are still the main methods for determining the size and shape of PEC
particles in solution or turbid dispersions. Therefore, a short summary on the history
of size and shape analysis of PEC nanoparticles, with a focus on light scattering and
microscopy, will be given.
2.1.1 Static Light Scattering
General experimental and theoretical principles and modalities on the SLS characterization of polydisperse particle systems can be found in the literature [24, 25]. To
the best of our knowledge, the group of Philipp and Dautzenberg were the first to
perform SLS studies on PEC dispersions. Comprehensive reviews on the approach
and modalities of applying SLS to PEC dispersions have been published [26, 27]. In
a related early article [28], Dautzenberg et al. reported SLS and viscosimetry results
on the influence of charge density and mixing ratio of PEC dispersions containing a
cationic copolymer of acrylamide and N-methyl-N,N-diethyl-N-ethylacrylate and
an anionic copolymer of acrylamide and acrylate (see Fig. 2).
2.1.2 Dynamic Light Scattering
General experimental and theoretical principles and modalities of DLS applied to
polydisperse particle systems can be found in the literature [24, 29]. The first DLS
work on PEC particles came to our knowledge from Dubin and Davis [30]
and Kabanov and Zezin [11]. Dubin and Murrell reported early DLS studies on
PEL/micelle complexes, including characterization of protein/PEL complexes
such as the BSA/PDADMAC system and its pH dependence by DLS [3] (see Fig. 3).
Kabanov and Zezin reported DLS studies on the complexation between synthetic
poly(N-dimethylaminoethylmethacrylate hydrochloride) (PDMAEMA) and
sodium polyphosphate and its dependence on the mixing ratio [11].
Recently, Lindhoud reported DLS titration studies on the reversibility and
relaxation behavior of PEC micelles composed of PDMAEMA, poly(acrylic
200
M. M€ uller