Thermo-induced multistep assembly of double-hydrophilic block copolypeptoids in water

• Published in: Colloid and polymer science Vol. 295; no. 8; pp. 1305 - 1312
• Main Authors: Bogomolova, Anna, Secker, Christian, Koetz, Joachim, Schlaad, Helmut
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2017; Springer Nature B.V
• Subjects: Aggregates; Aqueous solutions; Assembly; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Clearing; Collapse; Complex Fluids and Microfluidics; Crystallization; Dismantling; Food Science; Glycine; Heating; Invited Article; Nanotechnology and Microengineering; Photon correlation spectroscopy; Physical Chemistry; Polymer Sciences; Soft and Granular Matter; Polypeptoids; Self-assembly; Block copolymers; Thermoresponsive
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-017-4044-6

The aqueous solution behavior of thermoresponsive-hydrophilic block copolypeptoids, i.e., poly( N -( n -propyl)glycine) x - block -poly( N -methylglycine) y ( x  = 70; y  = 23, 42, 76), in the temperature range of 20–45 °C is studied. Turbidimetric analyses of the 0.1 wt% aqueous solutions reveal two cloud points at T cp ∼30 and 45 °C and a clearing point in between at T cl ∼42 °C. Temperature-dependent dynamic light scattering (DLS) suggest that right above the first collapse temperature, single polymer molecules assemble into large structures which upon further heating, i.e., at the clearing point temperature, disassemble into micelle-like structures. Upon further heating, the aggregates start to grow again in size, as recognized by the second cloud point, through a crystallization process. Graphical abstract ᅟ