Interfacial behaviour of short-chain fluorocarbon surfactants at the n-hexane/water interface: a molecular dynamics study.

The utilization of long-chain fluorocarbon surfactants is restricted due to environmental regulations, prompting a shift in the focus of research towards short-chain fluorocarbon surfactants. The present study employs molecular dynamics techniques to model the behaviour of potassium perfluorobutylsulfonate (PFBS) at the n-hexane/water interface, aiming to investigate the efficacy of short-chain fluorocarbon surfactants in enhancing oil recovery. The findings suggest that ionized PFBS has the ability to autonomously migrate to the oil/water interface, forming a layered thin film, with the sulfonic acid group being submerged in water, while the fluorocarbon chain is oriented towards the oil phase.

Physical breakdown of CH hydrate under stress: a molecular dynamics simulation study.

As a solid energy source, CH hydrate will inevitably break down physically as the result of geological movement or exploitation. Here, the molecular dynamics method was employed to simulate the uniaxial-deformation behavior of structure I (sI type) CH hydrate under stress. The stress increases regardless of whether the hydrate is stretched or squeezed, and other physical parameters also changed, such as hydrate cage numbers, order parameters, and the number of water molecules.

Molecular simulation of imperfect structure I CO hydrate growth in brine.

In order to investigate the viability of carbon dioxide (CO) storage in seawater, molecular dynamics techniques were employed to study the dynamic evolution of CO hydrate in saline water. The simulation was conducted under specific conditions: a temperature of 275 K, a pressure of 10 MPa and a simulated marine environment achieved using a 3.4 wt% sodium chloride (NaCl) solution.

Synthesis and drag reduction properties of a hydrophobically associative polymer containing ultra-long side chains.

Different from common hydrophobic associative polymers, a new hydrophobic associative polyacrylamide (HAPAM) with ultra-long side chains was synthesized and aimed to be used as drag reducer in this work. Firstly, a water-soluble hydrophobic monomer (named AT114) was obtained by alcoholysis reaction with acryloyl chloride and triton 114, then the drag reducer was obtained by radical copolymerization of AM, AMPS and AT114. The structures of AT114 and drag reducer were characterized by IR and NMR.