Thermoresponsive property of well-defined poly(N-methyl-N-n-propylacrylamide) and its copolymer architectures prepared by hydrosilylation-promoted group transfer polymerization

• Published in: Polymer (Guilford) Vol. 202; p. 122678
• Main Authors: Li, Jian, Mizutani, Shunsuke, Sato, Shin-ichiro, Narumi, Atsushi, Haba, Osamu, Kawaguchi, Seigou, Kakuchi, Toyoji, Shen, Xiande
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 12.08.2020; Elsevier BV
• Subjects: Abscisic acid; Aggregation behavior; Block copolymers; Chemical synthesis; Copolymers; Group transfer polymerization; Hydrosilylation; Polyacrylamide; Polymerization; Room temperature; Segments; Statistics; Thermoresponsive property; Group transfer polymerization; Thermoresponsive property; Polyacrylamide
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2020.122678

N-methyl-N-n-propylacrylamide (MnPAm) was polymerized using a versatile organocatalytic group transfer polymerization (GTP) system to afford the well-defined poly(N-methyl-N-n-propylacrylamide) (PMnPAm), in which a silyl ketene aminal was in-situ formed as the initiator by the B(C6F5)3-catalyzed 1,4-hydrosilylation of MnPAm and the stable hydrosilane of Me2EtSiH. After confirming the controlled/living feature for the hydrosilylation-promoted GTP system by the chain extension experiment, a series of copolymer architectures composed of the PMnPAm segment (A) as the thermoresponsive moiety and the poly(N,N-dimethylacrylamide) (PDMAm) segment (B) as the water-soluble one were synthesized using the sequential monomer addition method, i.e., AB-statistical copolymer, AB-diblock copolymer, and ABA- and BAB-triblock copolymers. The successful synthesis of PMnPAm provided careful insights into the thermoresponsive property with the cloud point temperature (Tc) around or below room temperature (29.3–14.5 °C) depending on the molecular weights. The thermoresponsive property for all of the prepared copolymer architectures of the AB-statistical copolymer, AB-diblock copolymer, and ABA- and BAB-triblock copolymers was described along with their aggregation behavior above the Tc for the thermoresponsive PMnPAm segment. [Display omitted] •N-methyl-N-n-propyl acrylamide (MnPAm) was applied as a monomer to a versatile group transfer polymerization (GTP) system using dimethylethylsilane (Me2EtSiH) and tris(pentafluorophenyl)borane (B(C6F5)3).•The hydrosilylation-promoted GTP allowed the precise control on the main chains to produce the PMnPAm with well-defined structures together with careful assignments for their thermoresponsive property depending on the molecular weights.•Synthesis of a series of copolymer architectures composed of MnPAm units as thermoresponsive moieties and DMAm units as water-soluble ones. The properties for all of the copolymer architectures were evaluated, particularly highlighting the importance of the amounts and the localized positions of the thermoresponsive A unit and the water-soluble B unit.