Aggregation, Gelation Instability, and Morphologies of Diblock Copolymers Consisting of Poly(p-benzamide) and Poly(m-benzamide)

作者：Kataoka Toshiyuki^*; Ohishi Tomoyuki; Yokozawa Tsutomu; Ikehara Takayuki

来源：Journal of Polymer Science Part B: Polymer Physics , 2010, 48(15): 1732-1739.

DOI：10.1002/polb.22038

• atomic force microscopy
• block copolymers
• dynamic light scattering
• gels
• micelles

The solution, gelation, and morphological properties of monodisperse aromatic polyamide diblock copolymers consisting of poly(p-benzamide) (PpBA), poly(m-benzamide) (PmBA), and poly(N-octyl m-benzamide) (POmBA) were investigated. The block copolymers of these polymers, PpBA-block-POmBA and PmBA-block-POmBA, formed spherical micelles or amorphous aggregates in many solvents in addition to physical gels at concentrations higher than 5 wt %. A temperature-induced sol-gel transition was also exhibited for PpBA-block-POmBA in solvents with high boiling points such as N,N-dimethylacetamide and N-methylpyrrolidone (NMP), although the transition was not entirely thermoreversible; the transition temperature decreased by annealing at similar to 80 degrees C. Dynamic light scattering measurements of the PpBA-block-POmBA/NMP solutions revealed that metastable micelles in the sol state reorganized into smaller micelles upon annealing at 90 degrees C. The block copolymer, which forms strong associations, exhibited some transient structure as indicated by the need to sufficiently anneal the solution to reach equilibrium. Network-like patterns with characteristic length of similar to 10 mu m appeared on the gel surfaces upon evaporation of volatile solvents such as dichloromethane and chloroform, in which the copolymers were observed to aggregate. The unique properties of the copolymers originate from interactions between the highly polar N-H aromatic polyamide blocks.

• 出版日期2010-8-1