Table 3.

Benefits and limitations arising from UCST based block copolymers and their assembly into switchable micelles.

Benefits	Limitations
• Often, steric restrictions in self-assembled block copolymer micelles are smaller than in covalently fused star polymers, therefore the UCST block usually resembles more strongly the phase behavior of the linear homopolymer. However, a shift in Tc UCST caused by the attached copolymer strongly depends on the UCST mechanism (ionic, non-ionic). • Dual thermoresponsive block copolymers (UCST-LCST) offer the self-assembly into in inside-out switchable micelles containing different microdomains in one polymer, which carries high potential for smart nanocarriers. • Despite of the thermoresponsive transition, precipitation can be strongly suppressed, especially in contrast to homopolymers. • First successful in vivo studies of UCST block copolymers as drug delivery systems for cancer therapy. Temporally, localized heat can be generated easily, which provides an advantage over LCST based systems requiring cooling. Combined photo-thermal and chemotherapy yields synergistic effects. • The modular structure of block copolymers can be extended to further blocks with specific properties.	• In particular, dually thermoresponsive block copolymers can have very complex phase transitions/assembly patterns. • Often the thermoresponsive behavior of the UCST segment is more strongly influenced by other segments than vice versa