Insights into the mechanical properties of a silicone oil gel with a ‘latent’ gelator, 1-octadecylamine, and CO₂ as an ‘activator’

Abstract

SummaryA detailed study of the rheological properties of silicone oil gels, made from a low-molecular-mass organic gelator, a combination of 1-octadecylamine (a latent gelator) and carbon dioxide (an ‘activating’ molecule), is reported. Information gleaned from the mechanical measurements is used to characterize the gel networks and how they respond to temperature and strain. It is shown, for example, that very precise measurements of the gel-to-sol transitions can be obtained from plots of viscosity versus temperature.

Systematic modifications of alkane-based molecular gelators and the consequences to the structures and properties of their gels

“…35 The rheological properties of the silicone oil gel were investigated in detail. 36 The storage modulus (G 0 ) remained higher than the loss modulus (G 00 ) in the 1-8 wt% concentration range and over a very wide range of frequencies within the linear viscoelastic region-these are true gels. Furthermore, changes in the value of G 0 versus temperature allowed the dependence of the SAFiN melting temperature, T g , on gelator concentration to be measured much more precisely than by the classical 'falling drop' 37 and inverted tube methods.…”

Structure and rheology of gel nanostructures from a vitamin C-based surfactant

“…In passing we note that the value of E a for the L-ASC12/water gel is comparable to that obtained with primary amines in silicone oil. 21 Dynamic mechanical measurements were performed to explore the viscoelastic properties of the gels produced by L-ascorbyl-dodecanoate. Fig.…”

Preparation of Novel W/O Gel-Emulsions and Their Application in the Preparation of Low-Density Materials

“…Furthermore, the G′ values of the gel-emulsions at different water content exhibit weak dependence on the frequencies below 300 rad s –1 , suggesting strongly that the gel-emulsions under study show good tolerance to external forces at the frequency range examined. However, the G′ values of the gel emulsions start to flocculate when the frequency reaches to 300 rad s –1 , indicating that the elasticity of the gel emulsions is sensitive to rapid movement and the physical junctions in the gel networks start to break at this critical frequency, specifically, following the equation of |η*| = [( G ′(ω) 2 + G ″(ω) 2 )/ω 2 ] 1/2 , where |η*| stands for the complex viscosity, ω is the angel frequency, and the meanings of other symbols are the same as discussed earlier. Figure shows the dependences of the complex viscosities of the gel emulsions on angle frequencies adopted in the frequency sweep measurements.…”