DMSO
Dimethyl sulfoxide
FRET
Fluorescence resonance energy transfer
HFIP
Hexafluoroisopropanol
NMR
Nuclear magnetic resonance
OCTMS
Octamethylcylotetrasiloxane
PDMS-DE Polydimethylsiloxane diepoxy terminated
PLLA
Poly(L-lactic acid)
PMMA
Poly(methyl methacrylate)
PPO
Poly(2,6-dimethyl-1,4-phenylene oxide)
PS
Polystyrene
PVAc
Poly(vinyl acetate)
PVCi
Poly(vinyl cinnamate)
PVF
Poly(vinyl formal)
SDS
Sodium dodecyl sulfate
1 Introduction
Imagine that you have synthesized a highly functional and advanced polymer. You
want to formulize it as nanoparticles or nanocapsules dispersed in an organic or an
aqueous medium. Unfortunately, your synthesis does not allow the use of emulsion
[1, 2], miniemulsion [3], or microemulsion polymerization [4, 5] because of
demanding reaction conditions. Or, let us imagine that you can perform the
aforementioned polymerization in dispersed media but you cannot get rid of
some residual monomer and/or initiator/catalyst without destabilizing the nanoparticles. What are the possibilities for preparation of polymer nanoparticles from
your polymer?
Burton and O’Farrel addressed these issues for a variety of elastomers and resin
latexes by inventing the solvent evaporation process from emulsion droplets,
also called the emulsion–solvent evaporation process [6]. In this process, a
pre-synthesized polymer or a mixture of different polymers are dissolved in a
suitable solvent and mixed with another immiscible liquid containing a surfactant
(Fig. 1). Afterwards, the solvent can be evaporated by heating the emulsion or by
applying a low vacuum [7]. Two years later, Vanderhoff et al. proposed many
possible examples in their patent application [8]. Thereafter, the process was
adopted mainly in pharmaceutical science to encapsulate drugs in biodegradable
polymers [9, 10], especially in micron-sized capsules and particles [11].
Although most of the reports deal with the preparation of microparticles,
nanosized particles and capsules are also accessible, usually by employing
ultrasonication to form very small droplets [12] from which the solvent is
evaporated. Usually, the continuous phase is an aqueous solution. Inverse systems
in which water is the solvent have been reported [13, 14] as well as non-aqueous
emulsions [15] such as dimethylformamide-in-paraffin [16], dichoromethanein-fluorinated solvent for microparticles [17], and formic acid-in-paraffin for
330
R.H. Staff et al.
Dimethyl sulfoxide
FRET
Fluorescence resonance energy transfer
HFIP
Hexafluoroisopropanol
NMR
Nuclear magnetic resonance
OCTMS
Octamethylcylotetrasiloxane
PDMS-DE Polydimethylsiloxane diepoxy terminated
PLLA
Poly(L-lactic acid)
PMMA
Poly(methyl methacrylate)
PPO
Poly(2,6-dimethyl-1,4-phenylene oxide)
PS
Polystyrene
PVAc
Poly(vinyl acetate)
PVCi
Poly(vinyl cinnamate)
PVF
Poly(vinyl formal)
SDS
Sodium dodecyl sulfate
1 Introduction
Imagine that you have synthesized a highly functional and advanced polymer. You
want to formulize it as nanoparticles or nanocapsules dispersed in an organic or an
aqueous medium. Unfortunately, your synthesis does not allow the use of emulsion
[1, 2], miniemulsion [3], or microemulsion polymerization [4, 5] because of
demanding reaction conditions. Or, let us imagine that you can perform the
aforementioned polymerization in dispersed media but you cannot get rid of
some residual monomer and/or initiator/catalyst without destabilizing the nanoparticles. What are the possibilities for preparation of polymer nanoparticles from
your polymer?
Burton and O’Farrel addressed these issues for a variety of elastomers and resin
latexes by inventing the solvent evaporation process from emulsion droplets,
also called the emulsion–solvent evaporation process [6]. In this process, a
pre-synthesized polymer or a mixture of different polymers are dissolved in a
suitable solvent and mixed with another immiscible liquid containing a surfactant
(Fig. 1). Afterwards, the solvent can be evaporated by heating the emulsion or by
applying a low vacuum [7]. Two years later, Vanderhoff et al. proposed many
possible examples in their patent application [8]. Thereafter, the process was
adopted mainly in pharmaceutical science to encapsulate drugs in biodegradable
polymers [9, 10], especially in micron-sized capsules and particles [11].
Although most of the reports deal with the preparation of microparticles,
nanosized particles and capsules are also accessible, usually by employing
ultrasonication to form very small droplets [12] from which the solvent is
evaporated. Usually, the continuous phase is an aqueous solution. Inverse systems
in which water is the solvent have been reported [13, 14] as well as non-aqueous
emulsions [15] such as dimethylformamide-in-paraffin [16], dichoromethanein-fluorinated solvent for microparticles [17], and formic acid-in-paraffin for
330
R.H. Staff et al.