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In a dynamic sense, the response of a gel to an alternating force (oscillation or vibration) will depend upon the period or frequency of vibration. As indicated here, even most simple liquids will exhibit some elastic response at shear rates or frequencies exceeding 5 x 10 6 cycles per second. Experiments on such short time scales probe the ...
Ormosils (organically modified silicate) are obtained when silane is added to gel-derived silica during sol–gel process. The product is a molecular-scale composite with improved mechanical properties. Sono-Ormosils are characterized by a higher density than classic gels as well as an improved thermal stability. An explanation therefore might ...
The first step of the sol-gel process is the creation of a colloidal suspension of solid particles known as a "sol". The precursors are a liquid alcohol such as ethanol which is mixed with a silicon alkoxide , such as tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), and polyethoxydisiloxane (PEDS) (earlier work used sodium silicates). [ 23 ]
Typically, gels are synthesized via sol-gel processing, a wet-chemical technique involving a colloidal solution (sol) that acts as the precursor for an integrated network (gel). There are two possible mechanisms whereby organogels form depending on the physical intermolecular inter-actions, namely the fluid-filled fiber and the solid fiber ...
Metallogels obtain multi-responsive property to widely environmental responses. In particular, metallogels which are made of transition metal and lanthanoid are thermo-responsive, [9] mechano-responsive, [10] chemo-responsive, [10] and photo-responsive. A metallogel system of Co/La shows inverse gel-sol transition when being heated to 100°C.
At that point in the reaction, which is defined as gel point, the system loses fluidity and viscosity becomes very large. The onset of gelation, or gel point, is accompanied by a sudden increase in viscosity. [3] This "infinite" sized polymer is called the gel or network, which does not dissolve in the solvent, but can swell in it. [4]
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Electrospinning extracts nanofibers from polymer solutions (synthesized by the sol-gel process) and collects them to form nonwoven nanofabrics. [19] A strong electric field is applied to the solution to charge the polymer strands. The solution is put into a syringe and aimed at an oppositely charged collector plate.