Telechelic Hybrid Poly(acrylic acid)s Containing Polyhedral Oligomeric Silsesquioxane (POSS) and Their Self-Assembly in Water

• Published in: Macromolecules Vol. 44; no. 17; pp. 6891 - 6898
• Main Authors: Zhang, Weian, Yuan, Jiayin, Weiss, Stephan, Ye, Xiaodong, Li, Chunliang, Müller, Axel H. E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 13-09-2011
• Subjects: Applied sciences; Exact sciences and technology; Inorganic and organomineral polymers; Physicochemistry of polymers; Preparation; 1,3-Dipolar cycloaddition; Acrylic acid copolymer; Hydrodynamic radius; End group; Silsesquioxane polymer; Butyl acrylate polymer; Telechelic polymer; Atom transfer polymerization; Silsesquioxane copolymer; Experimental study; Dimension spectrum; Hydrolysis; Azides; Monodispersed polymer; Triblock copolymer; Chemical modification; Polyhedral molecule; Preparation; Molecular aggregation; Aqueous solution; Nucleophilic substitution; Amphiphilic polymer
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma201152t

Telechelic (“dumbbell-shaped”) POSS-containing inorganic/organic hybrid poly(tert-butyl acrylate) (POSS-PtBA-POSS) was prepared by the combination of ATRP and the copper-catalyzed azide–alkyne “click” reaction. Telechelic bromoterminated PtBAs with different molecular weights were first prepared via ATRP using a dibromo-functionalized ATRP initiator; subsequently, the bromo groups were transformed to azido groups using sodium azide in DMF via nucleophilic substitution. The “click” coupling between azido-terminated PtBA and alkyne-functionalized POSS was successfully accomplished to afford telechelic POSS-PtBA-POSS, which is confirmed by NMR and GPC. The telechelic POSS-PtBA-POSS was then hydrolyzed to amphiphilic telechelic POSS-functional poly(acrylic acid) (POSS-PAA-POSS). The self-assembly behavior of POSS-PAA-POSS with three different molecular weights in aqueous solution at pH 8.5 was investigated by transmission electron microscopy, scanning electron microscopy, and light scattering (SLS, DLS). The results show that POSS-PAA40-POSS and POSS-PAA82-POSS can self-assemble in water into ellipsoidal aggregates with a moderately uniform size, whereas POSS-PAA140-POSS with a long PAA chain only self-assembles into aggregates with a broad size distribution. We discuss the formation of layered crystals of POSS within these aggregates.