A very well known temperature sensitive hydrogel is crosslinked poly(/V-isopropyl acrylamide) which has a lower critical solution temperature (LCST) at 31-33[degrees]C in water [1, 2).
P(NIPAAm-co-AAm) and p(NIPAAm-co-AAm)/XA hydrogels that contain crotonic acid (CA) exhibit a lover critical solution temperature (LCST) at 28[degrees]C, whereas p(NIPAAm-ce;-AAm)/IA, and P(NIPAAm-co-AAm)/ACA hydrogels exhibit a lover critical solution temperature at 30.
Upper critical solution temperature (UCST) phenomenon is observed for partially miscible blend whereas, upper order- disorder transition (UODT) is observed in corresponding block copolymer which is caused by unfavorable energies .
Another type of phase separation phenomenon beyond those typical phase separation behavior is called as lower critical solution temperature (LCST) observed in some polymer blends or lower disorder-order transition (LDOT) in the corresponding block copolymers [4-6].
Similarly, thermoresponsive polymers with Lower Critical Solution Temperature (LCST) have been investigated for various biomedical and pharmaceutical formulations.
Poly (N-isopropylacrylamide) is a thermoresponsive polymer having Lower Critical Solution Temperature at 32[degrees]C.
The polymer particles have a lower critical solution temperature
and the polymer particles are formed at a temperature above the lower critical solution temperature
Thermodynamics and Phase Equilibria * Introduction to free energy of mixing * Why entropy effects are small in polymers * Chemistry factors controlling miscibility * Blending principles and adhesion between polymers * Phase diagrams: lower critical solution temperature
, upper critical solution temperature
, generalized phase diagrams * Flory-Huggins equation * Copolymers and blending * Copolymer representations - temperature composition plots, miscibility maps
This suggests that the blend exhibits lower critical solution temperature
Poly (N-isopropylacrylamide) is a well-known example of a thermo-responsive polymer which exhibits lower critical solution temperature
or phase separation at about 32oC.
5) studied the phase behavior of a polystyrene/polyisoprene blend with an upper critical solution temperature
(UCST) in the presence of scC[O.
This paper reports preliminary results of the effect of shear flow on the phase behavior of two blends: a polystyrene/polyisobutylene (PS/PIB) blend that exhibits upper critical solution temperature
(UCST) phase behavior and polystyrene/poly(vinyl methyl ether) (PS/PVME) blends that show lower critical solution temperature
(LCST) phase behavior.