Precision syntheses and thermoresponsive properties for well-defined linear and/or architecturally controlled poly(N-substituted acrylamide)s are described together with their developmental history.

B(C ₆ F ₅ ) ₃ -catalyzed GTP synthesis of poly( N -isopropyl, N -methylacrylamide) as a new thermoresponsive material.

The controlled syntheses of glycerol-based polymers, involving poly(glycidol) (PG)-backbones and thermoresponsive oligo(oxyethylene)-side chains, are described. The organocatalytic ring-opening polymerizations of benzyl glycidyl ether (BnGE) were performed to produce poly(benzyl glycidyl ether)s (PBnGE_ns) in which the degree of polymerization (n) was predetermined, followed by the removal of the inherent protection groups. For these polymerization/deprotection stages, the synthesis of two major types of polymers is emphasized, in which one is “pristine” PG without any specific end-groups (PG_n) and the other is the α-end functionalized PG with hydrophobic aliphatic and aromatic groups (R-PG_n). The post-modification reactions based on the addition reactions of isocyanate derivatives to the hydroxyl side groups were adopted for PG_n and R-PG_n, thus producing poly[glycidyl oligo(oxyethylene)carbamate]s with diverse structures. The structures can generally be expressed as PG_n-EO_mR′ and R-PG_n-EO_mR′, where (i) the degree of polymerization (n), (ii) the alkyl group at the periphery of the side groups (R′), (iii) the number of oxyethylene chains (m), and (iv) the α-end group (R) can be independently controlled and/or selected. The effects of the parameters/structures (i)–(iv) on the thermoresponsive properties and the supporting data for the phase transitions in aqueous media are described in detail.

In this paper, we describe a comprehensive study of the thermoresponsive properties of statistic copolymers and multiblock copolymers synthesized by poly(glycidol)s (PG) and poly(ethyl glycidyl ether) (PEGE) with different copolymerization methods. These copolymers were first synthesized by ring-opening polymerization (ROP), which was initiated by tert-butylbenzyl alcohol (tBBA) and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2Λ⁵,4Λ⁵-catenadi(phosphazene) (t-Bu-P₄) as the catalyst, and then the inherent protective groups were removed to obtain the copolymers without any specific chain end groups. The thermoresponsive property of the statistic copolymer PG_x-stat-PEGE_y was compared with the diblock copolymer PG_x-b-PEGE_y, and the triblock copolymers were compared with the pentablock copolymers. Among them, PG-stat-PEGE, PG-b-PEGE-b-PG-b-PEGE-b-PG, and PEGE-b-PG-b-PEGE-b-PG-b-PEGE, and even the specific ratio of PEGE-b-PG-b-PEGE, exhibited LCST-type phase transitions in water, which were characterized by cloud point (T_cp). Although the ratio of x to y affected the value of the T_cp of PG_x-stat-PEGE_y, we found that the disorder of the copolymer has a decisive effect on the phase-transition behavior. The phase-transition behaviors of PG-b-PEGE, part of PEGE-b-PG-b-PEGE, and PG-b-PEGE-b-PG copolymers in water present a two-stage phase transition, that is, firstly LCST-type and then the upper critical solution temperature (UCST)-like phase transition. In addition, we have extended the research on the thermoresponsive properties of EGE homopolymers without specific α-chain ends.