2 research outputs found
Extended Charge-On-Particle Optimized Potentials for Liquid Simulation Acetone Model: The Case of Acetone–Water Mixtures
It is well-known
that classical molecular dynamics simulations
of acetone–water mixtures lead to a strong phase separation
when using most of the standard all-atom force fields, despite the
well-known experimental fact that acetone is miscible with water in
any proportion at room temperature. We describe here the use of a
charge-on-particle model for accounting for the induced polarization
effect in acetone–water mixtures which can solve the demixing
problem at all acetone molar fractions. The polarizability effect
is introduced by means of a virtual site (VS) on the carbonyl group
of the acetone molecule, which increases its dipole moment and leads
to a better affinity with water molecules. The VS parameter is set
by fitting the density of the mixture at different acetone molar fractions.
The main novelty of the VS approach lies on the transferability and
universality of the model because the polarizability can be controlled
without modifying the force field adopted, like previous efforts did.
The results are satisfactory also in terms of the transport properties,
that is, diffusivity and viscosity coefficients of the mixture
Dynamic Light Scattering and X‑ray Photoelectron Spectroscopy Characterization of PEGylated Polymer Nanocarriers: Internal Structure and Surface Properties
In this work, nanospheres and nanocapsules
are precipitated in
confined impinging jet mixers through solvent displacement and characterized.
Acetone and water are used as the solvent and antisolvent, respectively,
together with polymethoxypolyethylene glycol cyanoacrylate-<i>co</i>-hexadecylcyanoacrylate and Miglyol as the copolymer and
oil, respectively. Characterization is performed with dynamic light
scattering, with electrophoretic measurements, and for the first time
with X-ray photoelectron spectroscopy. Results show that the presence
of polyethylene glycol chains seems to be more pronounced on the surface
of nanospheres than on that of nanocapsules. The thickness of the
copolymer layer in nanocapsules ranges from 1 to 10 nm, depending
on the value of the oil:copolymer mass ratio. Fast dilution is confirmed
to have a positive effect in suppressing aggregation but can induce
further copolymer precipitation