Revisiting the Contribution of Additives to the Long-Term Mechanical Stability and Hydrolytic Resistance of Highly Crystalline Polylactide Fibers.

Additives are widely used to improve the processability, toughness, and hydrolytic resistance of poly(lactic acid) (PLA)-based materials. This study compares neat PLA fibers and fibers made from PLA blends with either poly(butylene succinate) (PBS) as a plasticizer or poly(d-lactic acid) (PDLA) as a nucleating agent. The fibers have been characterized with regard to their physical and structural properties after fabrication as well as after artificial aging at elevated temperature and humidity conditions.

Volatile Aroma Surfactants: The Evaluation of the Adsorption-Evaporation Behavior under Dynamic and Equilibrium Conditions.

Multicomponent heterogeneous systems containing volatile amphiphiles are relevant to the fields ranging from drug delivery to atmospheric science. Research presented here discloses the individual interfacial activity and adsorption-evaporation behavior of amphiphilic aroma molecules at the liquid-vapor interface. The surface tension of solutions of nonmicellar volatile surfactants linalool and benzyl acetate, fragrances as such, was compared with that of the conventional surfactant sodium dodecyl sulfate (SDS) under equilibrium as well as under no instantaneous equilibrium, including a fast-adsorbing regime.

Tensiometry as a Simple Analytical Method for Quantification of Solubility and Release of Aroma Molecules in Aqueous Media.

Dynamic tensiometry is shown to be a high-potential analytical tool in assessing physico-chemical characteristics of fragrance molecules, such as solubility limit, volatility as well as much rarely assessed interfacial activity of these amphiphilic molecules. Surface tension of aqueous solutions of selected essential oils has been measured as a function of time and fragrance concentration using maximum bubble pressure method. The effect of the temperature and saline solution on the rate of dissolution in water was assessed.

Aroma Molecules as Dynamic Volatile Surfactants: Functionality beyond the Scent.

Understanding of nonequilibrium processes at dynamic interfaces is indispensable for advancing design and fabrication of solid-state and soft materials. The research presented here unveils specific interfacial behavior of aroma molecules and justifies their usage as multifunctional volatile surfactants. As nonconventional volatile amphiphiles, we study commercially available poorly water-soluble compounds from the classes of synthetic and essential flavor oils.

Synergic Swelling of Interactive Network Support and Block Copolymer Films during Solvent Vapor Annealing.

We report the effect of "interactive" polymer network (PN) supports on the solvent-vapor processing of thin polymer films. Densely cross-linked surface-attached network exhibits under experimental time scale a glassy swelling behavior with the conformational states and solvent-uptake clearly sensitive to the degree of solvent vapor saturation in the atmosphere. Pretreatment of the thermally cured PN films by complete immersion or by swelling in saturated chloroform vapors facilitates relaxation of the residual stresses and induces irreversible changes to the network structure as revealed by the swelling/deswelling tests.

Enzyme-Compatible Dynamic Nanoreactors from Electrostatically Bridged Like-Charged Surfactants and Polyelectrolytes.

Reported is an unanticipated mechanism of attractive electrostatic interactions of fully neutralized polyacrylic acid (PAA) with like-charged surfactants. Amphiphilic polymer-surfactant complexes with high interfacial activity and a solubilization capacity exceeding that of conventional micelles are formed by bridging with Ca ions. Incorporation of a protease into such dynamic nanoreactors results in a synergistically enhanced cleaning performance because of the improved solubilization of poorly water-soluble immobilized proteins.

Morphology-Controlled Kinetics of Solvent Uptake by Block Copolymer Films in Nonselective Solvent Vapors.

We compare the swelling behavior of a compositionally symmetric diblock copolymer in films with nonbulk micellar morphology and with vertically oriented lamellae. The morphologies preformed by spin-coating from selective/nonselective solvents differ in shape and total area of the AB interfaces between incompatible units. Experimental measurements and dissipative particle dynamics (DPD) simulations demonstrate that AB interfaces dominate as the diffusion pathways of nonselective solvent molecules in strongly segregated films.