A Tale of Two Tails: Tail Ordering of Stoichiometric 1:1 DTAB:SDS Pairs Adsorbed at the Oil-Water Interface.

Cationic:anionic surfactant mixtures adsorbed at an oil-water interface stabilize foams in the presence of oil, making them essential to the oil, gas, and firefighting industries. The oil tolerance of foams stabilized by surfactant mixtures, relative to pure (unmixed) cationic and anionic surfactants, results from the mixtures' enhanced flexibility in tailoring the physicochemical properties of the interface. To judiciously employ these mixtures, it is necessary to characterize the structure-function property relationship of their surfactant monolayers that lend to oil-tolerant/intolerant foams.

Bulking up: the impact of polymer sterics on emulsion stability.

Encapsulation of hydrophobic active ingredients is critical for targeted drug delivery as water-insoluble drugs dominate the pharmaceutical marketplace. We previously demonstrated hexadecane-in-water emulsions stabilized with a pH-tunable polymer, poly(acrylic acid) (PAA), a steric layer preventing particle aggregation. Using vibrational sum frequency scattering spectroscopy (VSFSS), here we probe the influence of steric hindrance on emulsion colloidal stability by tailoring the molecular weight of PAA and by adding an additional methyl group to the polymer backbone poly(methacrylic acid) (PMAA) at pH 2, 4, and 6.

Two-photon excitation two-dimensional fluorescence spectroscopy (2PE-2DFS) of the fluorescent nucleobase 6-MI.

Base stacking is fundamentally important to the stability of double-stranded DNA. However, few experiments can directly probe the local conformations and conformational fluctuations of the DNA bases. Here we report a new spectroscopic approach to study the local conformations of DNA bases using the UV-absorbing fluorescent guanine analogue, 6-methyl isoxanthopterin (6-MI), which can be used as a site-specific probe to label DNA.

The Surface of Colloidal Metal-Organic Framework Nanoparticles Revealed by Vibrational Sum Frequency Scattering Spectroscopy.

Solvation shells strongly influence the interfacial chemistry of colloidal systems, from the activity of proteins to the colloidal stability and catalysis of nanoparticles. Despite their fundamental and practical importance, solvation shells have remained largely undetected by spectroscopy. Furthermore, their ability to assemble at complex but realistic interfaces with heterogeneous and rough surfaces remains an open question.

A Comparative Study of Cellulose Ethers as Thermotropic Materials for Self-Tracking Solar Concentrators.

The continuous growth in energy demand requires researchers to find new solutions to enlarge and diversify the possible ways of exploiting renewable energy sources. Our idea is the development of a solar concentrator based on trapping the luminous radiation with a smart window. This system is able to direct light towards the photovoltaic cells placed on window borders and produce electricity, without any movable part and without changing its transparency.