Although polymer particles with near-uniform
sizes below 200 nm can be produced, an excess amount ofsurfactant (50−100% of the polymer weight) is usually
required.
44,45
In addition, the most popular stabilizer used for
PLA emulsification in the pharmaceutical industry, poly(vinyl
alcohol),
46
is immiscible with PLA when melt-processed.
47
After screening various surfactants (data not shown), we found
that Polysorbate 80 (an ester of polyethoxylated sorbitan and
oleic acid) was effective in stabilizing these emulsions at a very
low surfactant-to-polymer weight ratio of 3:100. Using a
minimal amount of surfactant avoids property changes induced
by the residual chemical