Micellar Parameters of Aqueous Solutions of Tween 20 and 60 at Different Temperatures: Volumetric and Viscometric Study

Abstract

Density, viscosity and speed of sound of aqueous solutions of nonionic surfactants such as polyoxyethylene (20) sorbitan monolaurate (Tween 20) and polyoxyethylene (20) sorbitan monostearate (Tween 60) at T = 293, 303 and 313 K are reported. From these measured values different parameters such as, for example, isentropic compressibility, molecular free length, acoustic impedance, primary hydration numbers and internal pressure have been calculated and employed to discuss molecular packing, structural alteration and molecular interactions. The variation in these parameters with temperature indicates that the mobility of surfactant molecules increases the disordered state of the liquid (surfactant + water) due to irregular packing of the molecules. Also, for Tween 20 solutions, more conversion to bulk water of the structured water molecules was observed, obtaining lower compressibilities and higher values of hydration numbers as well as internal pressure for a given T.

Printing Life‐Inspired Subcellular Scale Compartments with Autonomous Molecularly Crowded Confinement

“…On the other hand, it was not possible to produce fL‐scale droplets at higher F108 concentrations, the resulting viscosity falling outside from the printable regimes of the Derby plot (see Figure S1 in the Supporting Information), a convenient representation of the fluid properties (viscosity, surface tension, droplet size, and speed) for inkjet printing. As a result, the surfactants at the chosen concentrations (F108 0.03% w/v, Tween‐20 0.05% v/v) maintain the droplet viscosity to values similar to unmodified aqueous solutions (1–2 mPa s), which are compatible with inkjet printing.…”

“…Along with the stabilization of water/oil interface, the surfactants can modify the ink viscosity and the surface tension, which are both fundamental parameters to ensure fluid printability in inkjet printing . In particular, F108 can slightly increase the ink viscosity already in the 1–4 w/v% range, whereas the Tween‐20 effect is in comparison significantly lower . In this regard, it was possible (Figure S3, Supporting Information) to produce fL‐droplets at F108 concentrations as high as 3% w/v, corresponding to the typical viscosity limit for inkjet printing of about 20–30 mPa s .…”

A New Generation of Dihydropyridine Calcium Channel Blockers: Photostabilization of Liquid Formulations Using Nonionic Surfactants

“…Its ability to improve drug water solubility and emulsion formulations is especially applied in the pharmaceutical field [28]. Because of their structure, which limits the presence of water in the internal sites, micelles formed by nonionic amphipathic surfactants like T20 provide a favorable environment to host amphiphilic drugs [29].…”

Preparation, characterisation and biological evaluation of biopolymer-coated multi-walled carbon nanotubes for sustained-delivery of silibinin

“…A possible explanation underlying this differential effect of polysorbates is that, the molecular configuration of polysorbate 20 is more stabilised and highly structured as more bulk water is converted from the structured water molecules. Therefore, total weight loss observed was considerably higher as the decomposition temperature of MWSB-T20 increased 47 . However, polysorbate 80 was more thermally stable because it contains a mixture of multiple different polymer chain lengths.…”