Behavior of ATRP-derived styrene and 4-vinylpyridine-based amphiphilic block copolymers in solution

• Published in: Colloid and polymer science 2018-07, Vol.296 (7), p.1127-1135
• Main Authors: Leimenstoll, Marc C., Menzel, Henning
• Format: Article
• Language: English
• Subjects: Anionic polymerization; Block copolymers; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Copolymers; Ethanol; Food Science; Ionomers; Micelles; Molecular chains; Nanotechnology and Microengineering; Original Contribution; Physical Chemistry; Polydispersity; Polymer Sciences; Polymerization; Polystyrene resins; Soft and Granular Matter
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-018-4330-y

The reaction sequence of (i) styrene (St) and (ii) 4-vinylpyridine (4VP) employing atom transfer radical polymerization (ATRP) with Cu(I)Cl/Me 6 TREN as the catalyst is known to lead to poly(styrene- b -4-vinylpyridine) (PS- b -P4VP) block copolymers with narrow molecular weight distributions and is well-controlled for both the styrene and the successive 4VP polymerization. Block copolymers derived by this reaction sequence can easily be converted to amphiphilic species by quarternization of the P4VP block. It was found that the behavior of ATRP-derived PS n - b -P4VP m + ⋅MeI − ionomers in solution is similar to the behavior of anionically derived ionomers. This indicates that the minor difference in polydispersity and chain termini in particular does not influence the colloidal characteristics significantly. Thus, ATRP was proven to be a valuable alternative to sensitive anionic polymerization technique to produce amphiphilic block copolymer systems. Additionally, it was found that PS n - b -P4VP m + ⋅MeI − ionomers with short P4VP m + ⋅MeI − and long PS blocks self-assemble in dioxane to “inverse” amphiphilic micelles and undergo a morphological transition to “regular” micelles upon slow addition of ethanol.