title: Enhancing gelation ability of a dendritic gelator through complexation with a polyelectrolyte.
abstract: A poly(urethane amide) (PUA) dendron with long alkyl chains on its periphery was synthesized and then attached to the backbone of a polyelectrolyte, in which each unit contained a positive charge, by ionizing the carboxyl groups on the apexes of the dendrons to form a dendronized polymer. We found that both the PUA dendron and the dendronized polymer could form organogels in toluene. Interestingly, both the minimum gelation concentration and the gelation time of the dendronized polymer gelator were greatly reduced compared with the dendron alone. Our investigations showed that in the gel phase the intermolecular hydrogen bonding between adjacent dendrons creates similar supramolecular structures in both the dendron and the dendronized polymer gelator, which immobilize solvent molecules by means of interactions between dendrons and solvent molecules. Further studies on the gelation kinetics indicated that the polyelectrolyte backbone plays an important role in prearranging the attached dendritic gelators orderly and quickly into the supramolecular structures through a nucleation-elongation mechanism. Therefore, the gel-forming ability of the dendritic PUA gelator is enhanced by being complexed with the polyelectrolyte. In this work, this positive macromolecular effect is discussed in detail.
authors.affiliation: The Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
authors.forename: Zijian
authors.initials: Z
authors.lastname: Zhang
authors.forename: Miao
authors.initials: M
authors.lastname: Yang
authors.forename: Xinjun
authors.initials: X
authors.lastname: Zhang
authors.forename: Lichu
authors.initials: L
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Wang