A RAFT copolymerization of NIPAM and HPMA and evaluation of thermo-responsive properties of poly(NIPAM-co-HPMA). Issue 92 (20th September 2016)

• Record Type: Journal Article
• Authors: Luan, Bao; Muir, Benjamin W.; Zhu, Jin; Hao, Xiaojuan
• Is Part Of: RSC advances. Volume 6:Issue 92(2016)
• Page Start: 89925
• Page End: 89933
• Publication Date: 2016-09-20
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra22722h
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : 66 (co)polymers of NIPAM and HPMA with varying MW, composition, and end functionality were synthesized by RAFT polymerization and their thermo-responsive properties were systematically evaluated. Abstract : Poly( N -isopropylacrylamide) (PNIPAM) has attracted intensive interest for bio-medical applications due to its unique thermal properties whereby it displays a lower critical solution temperature (LCST) close to body temperature. It is well known that the LCST of PNIPAM can be tuned by incorporating a second component. In this study, a library of (co)polymers of NIPAM and N -(2-hydroxypropyl) methacrylamide (HPMA) with varying molecular weight (MW), composition, and end functionality were synthesized by Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization to systematically investigate how these factors influence their thermo-responsive behavior. Our findings include: (1) the LCST of NIPAM- co -HPMA (co)polymers increases with HPMA content ( F HPMA ) in the temperature range from 29 to 92 °C; (2) the LCST of the polymers is significantly higher when the hydrophobic dithiobenzoate end-group is converted to a thiol-group, however, this influence becomes less pronounced for high MW polymers; (3) the MW of the copolymers has a negligible influence on the LCST. This systematic study investigating the effects of such influencing factors as MW, end group, and polymer composition on the LCST of NIPAM-containing polymers provides new insights into this class of thermo-responsive polymers.