Global Information Lookup Global Information

Lower critical solution temperature information


The lower critical solution temperature (LCST) or lower consolute temperature is the critical temperature below which the components of a mixture are miscible in all proportions.[1][2] The word lower indicates that the LCST is a lower bound to a temperature interval of partial miscibility, or miscibility for certain compositions only.

The phase behavior of polymer solutions is an important property involved in the development and design of most polymer-related processes. Partially miscible polymer solutions often exhibit two solubility boundaries, the upper critical solution temperature (UCST) and the LCST, both of which depend on the molar mass and the pressure. At temperatures below LCST, the system is completely miscible in all proportions, whereas above LCST partial liquid miscibility occurs.[3][4]

In the phase diagram of the mixture components, the LCST is the shared minimum of the concave up spinodal and binodal (or coexistence) curves. It is in general pressure dependent, increasing as a function of increased pressure.

For small molecules, the existence of an LCST is much less common than the existence of an upper critical solution temperature (UCST), but some cases do exist. For example, the system triethylamine-water has an LCST of 19 °C, so that these two substances are miscible in all proportions below 19 °C but not at higher temperatures.[1][2] The nicotine-water system has an LCST of 61 °C, and also a UCST of 210 °C at pressures high enough for liquid water to exist at that temperature. The components are therefore miscible in all proportions below 61 °C and above 210 °C (at high pressure), and partially miscible in the interval from 61 to 210 °C.[1][2]

  1. ^ a b c P.W. Atkins and J. de Paula, "Atkins' Physical Chemistry" (8th edn, W.H. Freeman 2006) pp. 186-7
  2. ^ a b c M. A. White, Properties of Materials (Oxford University Press 1999) p. 175
  3. ^ Charlet G, Delmas G (1981) Polymer 22:1181–1189
  4. ^ Charlet G, Ducasse R, Delmas G (1981) Polymer 22:1190–1198

and 21 Related for: Lower critical solution temperature information

Request time (Page generated in 1.0578 seconds.)

Lower critical solution temperature

Last Update:

The lower critical solution temperature (LCST) or lower consolute temperature is the critical temperature below which the components of a mixture are...

Word Count : 1790

Upper critical solution temperature

Last Update:

The upper critical solution temperature (UCST) or upper consolute temperature is the critical temperature above which the components of a mixture are...

Word Count : 579

Entropy of mixing

Last Update:

molecules. For some systems this can lead to a lower critical solution temperature (LCST) or lower limiting temperature for phase separation. For example, triethylamine...

Word Count : 4758

Nile red

Last Update:

poly(N-isopropyl acrylamide)s with core–shell morphology below the lower critical solution temperature". RSC Advances. 4 (92): 50932–50937. doi:10.1039/C4RA10076J...

Word Count : 739

Hydroxypropyl cellulose

Last Update:

hydrophobic and hydrophilic groups, so it has a lower critical solution temperature (LCST) at 45 °C. At temperatures below the LCST, HPC is readily soluble in...

Word Count : 627

Methyl cellulose

Last Update:

needed] Methyl cellulose has a lower critical solution temperature (LCST) between 40 °C and 50 °C.[citation needed] At temperatures below the LCST, it is readily...

Word Count : 2171

Spinodal

Last Update:

with temperature and concentration, and the binodal and spinodal meet at the critical or consolute temperature and composition. For binary solutions, the...

Word Count : 713

Curie temperature

Last Update:

induced magnetism. The Curie temperature is named after Pierre Curie, who showed that magnetism was lost at a critical temperature. The force of magnetism...

Word Count : 4786

Polymer

Last Update:

critical solution temperature phase transition (UCST), at which phase separation occurs with cooling, polymer mixtures commonly exhibit a lower critical solution...

Word Count : 7697

Nanoparticle drug delivery

Last Update:

water at room temperature but precipitates reversibly from when the temperature is raised above its lower critical solution temperature (LCST), changing...

Word Count : 5293

Krafft temperature

Last Update:

equal to critical micelle concentration (CMC). Below the Krafft temperature, the maximum solubility of the surfactant will be lower than the critical micelle...

Word Count : 260

Hydrogel

Last Update:

solution temperature (UCST) or lower critical solution temperature (LCST). UCST polymers increase in their water-solubility at higher temperatures, which...

Word Count : 7688

Cononsolvency

Last Update:

a decreased volume phase transition temperature, the thin-film analogy of a lower critical solution temperature. These experimental studies are supported...

Word Count : 1868

Austenite

Last Update:

iron or a solid solution of iron with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K (727 °C);...

Word Count : 1558

Electroactive polymer

Last Update:

microfluidic devices are mainly based on temperature-responsive polymers with lower critical solution temperature (LCST) characteristics, which are controlled...

Word Count : 3922

Supercritical fluid

Last Update:

A supercritical fluid (SCF) is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist...

Word Count : 4781

Heat treating

Last Update:

are often heated to a temperature that is just above the upper critical temperature, in order to prevent the grains of solution from growing too large...

Word Count : 5793

Supersaturation

Last Update:

at the lower temperature is achieved. Impurities remain in the supernatant liquid. In some cases crystals do not form quickly and the solution remains...

Word Count : 2164

Critical relative humidity

Last Update:

The critical relative humidity (CRH) of a salt is defined as the relative humidity of the surrounding atmosphere (at a certain temperature) at which the...

Word Count : 284

Critical micelle concentration

Last Update:

active substances and electrolytes. Micelles only form above critical micelle temperature. For example, the value of CMC for sodium dodecyl sulfate in...

Word Count : 1224

Critical dimension

Last Update:

physics, a critical dimension is the dimensionality of space at which the character of the phase transition changes. Below the lower critical dimension...

Word Count : 1611

PDF Search Engine © AllGlobal.net