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The amount of relaxation which takes place is a function of time, temperature and stress level, thus the actual effect it has on the system is not precisely known, but can be bounded. Stress relaxation describes how polymers relieve stress under constant strain. Because they are viscoelastic, polymers behave in a nonlinear, non-Hookean fashion. [1]
The phase transition is a manifestation of competition among the three forces which contribute to the osmotic pressure in the gel: The positive osmotic pressure of (+) hydrogen ions; The negative pressure due to polymer-polymer affinity; The rubber-like elasticity of the polymer network
Electrophoresis is the motion of charged dispersed particles or dissolved charged molecules relative to a fluid under the influence of a spatially uniform electric field. As a rule, these are zwitterions with a positive or negative net charge. [1] Electrophoresis is used in laboratories to separate macromolecules based on their charges.
Gel electrophoresis uses a gel as an anticonvective medium or sieving medium during electrophoresis. Gels suppress the thermal convection caused by the application of the electric field and can also serve to maintain the finished separation so that a post-electrophoresis stain can be applied. [ 3 ]
Polyacrylamide gel electrophoresis (PAGE) is a technique widely used in biochemistry, forensic chemistry, genetics, molecular biology and biotechnology to separate biological macromolecules, usually proteins or nucleic acids, according to their electrophoretic mobility. Electrophoretic mobility is a function of the length, conformation, and ...
The stress relaxation modulus () is the ratio of the stress remaining at time after a step strain was applied at time =: = (), which is the time-dependent generalization of Hooke's law . For visco-elastic solids, G ( t ) {\displaystyle G\left(t\right)} converges to the equilibrium shear modulus [ 4 ] G {\displaystyle G} :
Schematic of the evolution of the instantaneous modulus E(t,T) in a static relaxation test. t is the time and T is the temperature. Consider the relaxation modulus E at two temperatures T and T 0 such that T > T 0. At constant strain, the stress relaxes faster at the higher temperature.
In polymer chemistry, gelation (gel transition) is the formation of a gel from a system with polymers. [1] [2] Branched polymers can form links between the chains, which lead to progressively larger polymers. As the linking continues, larger branched polymers are obtained and at a certain extent of the reaction, links between the polymer result ...