Impact of Molecular Structure on Properties of n-Hexadecane and Alkylbenzene Binary Mixtures.

Because of the complexity of petroleum-based fuels, researchers typically use simplified mixtures, known as surrogates, to study combustion behavior and to attempt to identify how physical properties are related to combustion. The process of determining the surrogate composition to yield a desired set of thermophysical properties can be a complicated and time-consuming task. As a result, the use of computer simulations to narrow the number of possible surrogate compositions is beginning to be explored.

Luminescent tunable polydots: Charge effects in confined geometry.

Long-lived soft nanoparticles, formed by conjugated polymers, constitute a new class of far-from-equilibrium responsive structures for nano-medicine. Tethering ionizable groups to the polymers enables functionality. However concurrently, the ionic groups perturb the delicate balance of interactions that governs these particles.

Structure of Rigid Polymers Confined to Nanoparticles: Molecular Dynamics Simulations Insight.

Nanoparticles (NPs) grafted with organic layers form hybrids able to retain their unique properties through integration into the mesoscopic scale. The organic layer structure and response often determine the functionality of the hybrids on the mesoscopic length scale. Using molecular dynamics (MD) simulations, we probe the conformation of luminescent rigid polymers, dialkyl poly(p-phenylene ethynylene)s (PPE), end-grafted onto a silica nanoparticle in different solvents as the molecular weights and polymer coverages are varied.

Internal Correlations and Stability of Polydots, Soft Conjugated Polymeric Nanoparticles.

Conjugated polymers collapsed into long-lived highly luminescent nanoparticles, or polydots, have opened a new paradigm of tunable organic particles with an immense potential enhancing intracellular imaging and drug delivery. Albeit the chains are not in their equilibrium conformation and are not confined by cross-links, they remain stable over astounding long times. Using fully atomistic molecular dynamics simulations with an innovative method to controllably collapse an inherently rigid polymer, we determined for the first time the internal structure and stability of polydots made of dialkyl--phenylene ethynylene, immersed in water, a biological relevant medium.

Conformational study of a single molecule of poly para phenylene ethynylenes in dilute solutions.

The conformation of single molecules of dialkyl poly para phenylene ethynylenes (PPEs), electro-active polymers, is studied in solutions using molecular dynamics simulations. The conformation of conjugated polymers affects their electro-optical properties and therefore is critical to their current and potential uses, though only limited theoretical knowledge is available regarding the factors that control their configuration. The present study investigates the affects of molecular parameters including molecular weight of the polymer and chemical structure of the side chains of PPEs in different solvents on the conformation of the polymers.