OBJECTIVES Microencapsulation of drugs into preformed polymers is commonly achieved through solvent evaporation techniques or spray drying. We compared these encapsulation methods in terms of controlled drug release properties of prepared microparticles and investigated the underlying mechanisms responsible for the 'burst release' effect. METHODS Using two different pH-responsive polymers wit...

We report of a method for fabricating two-dimensional, regular arrays of polymer microlenses with focal lengths variable between 0.2 and 4.5 mm. We first make concave microlenses by ink-jetting solvent on a polymer substrate with a commercial drop-on-demand device. Solvent evaporation restructures the surface by a series of combined effects, which are discussed. In the second step we obtain con...

In this study, we first investigated changes seen in electrical and optical properties of a polymer light-emitting diode due to using different kinds of solvents and their mixture. Two-layer light emitting diodes with organic small molecules doped in a PVK polymer host were fabricated using (i) non-aromatic solvent chloroform with a high evaporation rate; (ii) aromatic solvent chlorobenzene wit...

This paper describes a robust and rapid procedure for measuring chlorophyll using a microplate reader. The procedure enables direct translation of any published equation developed on a 1-cm pathlength spectrophotometer to any format microplate with any sample volume. Chlorophylls were extracted with methanol because it is compatible with cheap polystyrene plates; however, the principles apply t...

A coarse-grained lattice-gas model in three dimensions is developed to study the self-assembly of nanoparticles into micrometer-sized rings from a thin liquid film containing the nanoparticles. The model describes the nanoparticles as well as the solvent on length scales that are typical of the solvent bulk correlation length. Morphologies obtained from simulations of the model resemble recent ...

Spin-coating of chalcogenide glass is a low-cost, scalable method to create optical grade thin films, which are ideal for visible and infrared applications. In this paper, we study the influence of annealing on optical parameters of As(2)S(3) films by examining UV-visible and infrared spectroscopy and correlating the results to changes in the physical properties associated with solvent removal....

BACKGROUND Paint laden with polychlorinated biphenyls (PCBs) often acts as a point source for environmental contamination. It is advantageous to address contaminated paint before the PCBs transport to surrounding media; however, current disposal methods of painted material introduce a variety of complications. Previous work demonstrates that PCBs can be broken down at ambient temperatures and p...

We report the 790 nm photofragmentation of mass-selected I2 2 •Arn clusters, n51 to 27. We determine the I1I caging efficiency as a function of the number of solvent Ar atoms and compare these results with I2 2 in CO2 clusters. Caging is much less effective with Ar. In addition to ‘‘normal’’ caged photoproducts ~I2 2 •Arm , where m,n!, the evaporation process following photoexcitation produces ...

Herein, the numerical simulation of polymeric membrane formation is investigated when a coupling between phase separation and solvent evaporation occurs. A binary polymer/solvent system considered simulations were performed in 2D geometries, first horizontal plan, then vertical cross-section plan. The was simulated using Cahn-Hilliard equations Flory-Huggins theory used to describe thermodynami...