Mechanism of solvent entrapment within the network scaffolding in organogels: thermodynamic and kinetic investigations

Abstract

A detailed investigation on the thermodynamic behaviour of the physical and chemical organogels, using differential scanning calorimetry (DSC) and modulated thermogravimetric analysis (MTGA), is presented. Aluminium soap of fatty acid was used as the physical gelator and in situ crosslinking of siloxane copolymer was used for chemical gelation. The effects of the type and concentration of the gelators and the corresponding mesh‐size distribution of the gel network scaffolding on the trapped‐solvent crystallization, melting and evaporation mechanism, and kinetics are examined. It appears that the kinetics of crystallization of the trapped‐solvent are significantly affected by the quality of the gel network scaffolding and can be treated successfully by the Avrami equation of crystallization. From the melting behaviour of the entrapped‐solvent crystallites, quantitative information about the number of solvent molecules bound per molecule of the gelator has been extracted. The effect of gelation network structure on the kinetics of evaporation of the solvent from the gel network scaffolding has been evaluated. DSC appears to be the reliable technique to evaluate the population distribution of solvent molecules trapped in the gel network scaffolding. Copyright © 2003 Society of Chemical Industry

Nanostructuring fiber morphology and solvent inclusions in 12-hydroxystearic acid / canola oil organogels

“…The samples were placed on Whatman number 5 15 cm papers and the oil mobility was measured at 20°C for 1 h by measuring the radius of exuded oil into the filter paper in time. [36]. Any variation in the crystallization enthalpies of the trapped solvent in the presence of the supramolecular network, gives important information about the physico-chemical process that governs the behavior of the gel systems [36].…”

“…[36]. Any variation in the crystallization enthalpies of the trapped solvent in the presence of the supramolecular network, gives important information about the physico-chemical process that governs the behavior of the gel systems [36]. Using DSC sweeps (Fig.…”

Protein/DNA/Inorganic Materials: DNA Binding to Layered α‐Zirconium Phosphate Enhances Bound Protein Structure and Activity

“…Therefore, developing novel methods to improve the bound-enzyme activity is of intense interest. [5] Here, we show that bound-protein behavior is improved to a significant extent by double-helical DNA. This is also the very first example of DNA binding to negatively charged layered inorganic materials, and this observation opens new possibilities for applications in gene or RNA delivery.…”

Swelling behavior and characterization of alcohol-specific superabsorbing gels based on acrylic acid and allyl tetrasodium thiacalix[4]arene tetrasulfonate

“…Organogels are materials, which can solidify organic solvents; they may be composed of low molecular weight or polymeric materials [1]. Organogels can be applied in different areas, such as in the controlled release of drugs and fragrances [2][3][4], and the surfactant industry [5]. Also, they have been used as fuel gels, particularly in outdoor applications for warming, cooking, boiling water, fire starters, or hand sanitizers [2,6].…”

“…In 2003, Yang has synthesized gels based on poly(N-isopropyl acrylamide-NaAMPS), which can absorb ethanol up to 70 g/g [9]. In 2004, Xie synthesized gels of copolymer (2-acrylamido-2-methylpropane sulfonic acid (AMPS) and acrylamide (AM)) that can absorb ethanol and methanol as high as 24 and 32 g/g, respectively [5]. In 2007, Zhao and liu prepared organogels based on crosslinked PAA using (Zn +2 , Cd +2 and Ni +2 ) for absorption of ethanol.…”