LCST, lower critical solution

AAM, acrylamide NMAAM, N-methyl acrylamide NEAAM, N-ethyl acrylamide NNBAAM, N-n-butyl acrylamide NTBAAM, N-t-butyl acrylamide NIPAAM, N-isopropyl acrylamide LCST, lower critical solution temperature TEMED, Tetramethylethylenediamine PBS, phosphate-buffered saline AIBN, 2,2 azobis(isobutyronitrile). 

Now about an LCST (lower critical solution temperature, see MT Figure 9.3). If we blend below this temperature, we can obtain a homogeneous mixture. Subsequent heating to above the LCST can resnlt in segregation the rapid cooling in an injection monlding machine does not allow to nndo this. 

Further heating led to liquid-liquid phase separation observed as a cloud point. This is an example of LCST (lower critical solution temperature) behavior. 

Figure 8.2 Schematic phase diagrams for thermoplastic-epoxy monomer (diglycidyl ether of bisphenol A) blends, (CPC = cloud point curve, and VC = vitrification curve), (a) and (b) UCST (upper critical solution temperature) behaviour for PPE and PEI (respectively) - DGEBA n = 0.15 (c) LCST (lower critical solution temperature) behaviour for PES-DGEBA y n = 0.15. (Pascault and Williams, 2000 - Copyright 2001. Reprinted by permission of John Wiley Sons Inc.)...

Figure 3 The composition-temperature diagram for pure poly-olefins showing UCST (upper critical solution temperature) and LCST (lower critical solution temperature) behaviour (because of the nature of this mixture, the UCST cannot be observed and therefore is dotted)...

CD Circular dichroism Die Differential interference contrast DLS Dynamic light scattering FTIR Fourier-transform infrared LSCM Laser scanning confocal microscopy LCST Lower critical solution temperature Me Methyl... 

Fig. 4 Formation of a core-shell sphere upon heating an aqueous PNlPAM-g-poly(ethylene oxide) (PBO) copolymer solution black PNIPAM backbone and grey PEO grafts. LCST lower critical solution temperature [170]...

LLE strongly depends on the temperature and the molecular weight. Typically, two LLE areas are observed, one at low tanperatures (UCST = upper critical solution temperature) and one at high temperatures (LCST = lower critical solution temperature). LCST is typically observed at temperatures between the boiling point and the critical temperature of the solvent. 

PPE Poly(2,6-dimethyl 1,4-phenylene LCST Lower Critical Solution... 

LCST lower critical solution temperature SEBS styrene-ethylene/butene-styrene three... 

Interesting properties can be engineered into these materials by copolymerization. Copolymerization of 2-ethylacrylic acid or MAA with iV-[4-(phe-nylazo)phenyl]methacrylamide, a photosensitive monomer, results in polymers in which the interaction with lipid biolayers can be photoregulated [10, 11]. Thermally reversible polymers can be produced from poly(iV-isopropylacryla-mide), which is a water-soluble polymer at room temperature. The LCST (lower critical solution temperature) of the homopolymer is 32 °C at this temperature a reversible phase separation occurs. This LCST can be adjusted by copolymerization with more or less hydrophilic monomers. 

Nies, E., Stroeks, A., Simha, R., and Jain, R. K., LCST [lower critical solution temperature] phase behavior according to the Simha-Somcynsky theory apphcation to the n-hexane/polyethylene system. Colloid Polym. Sci., 268, 731-743 (1990). 

In contrast to organosoluble polymers, for most known water-based nonionic polymers, the quaUty of water as a solvent decreases upon an increase in temperature. This is known as LCST (lower critical solution temperature) behavior [144], Experimental observations of LCST behavior (thermoinduced collapse) of neutral stars or spherical polymer brushes in water are rare [145, 146], and do not yet provide systematic relationships between the LCST and the degree of branching. 

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