MURAGAKI Yoshihiro    Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine    Position   Visiting Professor
Article types	Original article
Language	English
Peer review	Peer reviewed
Title	Alteration of the upper critical solution temperature (UCST) behavior of the nonionic polymer poly(N-acryloyl-nipecotamide) by its terminal group
Journal	Formal name：European Polymer Journal Abbreviation：Eur. Polym. ISSN code：0014-3057/1873-1945
Domestic / Foregin	Foregin
Publisher	Elsevier
Volume, Issue, Page	220,pp.113454
Total page number	9
Author and coauthor	AKIYAMA Yoshikatsu†*, OSAWA Shigehito, MASAMUNE Ken, MURAGAKI Yoshihiro
Authorship	Last author
Publication date	2024/11/15
Summary	The effect of terminal groups on the cloud points (CPs) of non-ionic polymers with upper critical solution temperature (UCST) has been a topic of interest, but detailed studies are limited. This research examines how the terminal groups of poly(N-acryloyl-nipecotamide)s (PNANAms) influence their CPs in aqueous solutions. PNANAms with different molecular weights (Mn) ranging from 4,100 to 34,300 and varied terminal groups were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. The temperature-dependent optical transmittance measurements revealed that CPs were influenced by not only Mn and polymer concentration but also the terminal groups. PNANAms with low Mn (Mn ≥ 7,500) and hydrophobic (dodecyl) terminal groups exhibited poor solubility, while those with moderate Mn (Mn ≤ 10,200) and hydrophilic (maleimide or carboxylic) terminal groups dissolved easily in water. PNANAms with high Mn (Mn = 34,300), however, showed poor solubility, likely due to strong inter- and intramolecular hydrogen bonding, which increased their CP. PNANAms with low Mn (Mn = 4,100) and hydrophobic terminals, as well as those with moderate Mn (13,200 ≤ Mn ≤ 18,200) and hydrophilic terminals, exhibited CPs in solution. The CP of PNANAms with carboxylic terminals was affected by pH due to the deprotonation of these groups. Phase-contrast microscopy was used to directly observe polymeric aggregates, and temperature-dependent aggregation and dispersion were explained by hydrogen bonding among PNANAm chains. Finally, a cell viability assay was performed to explore the potential of PNANAms in biomaterials and regenerative medicine applications.
DOI	10.1016/j.eurpolymj.2024.113454