A. Bogomolova, C. Secker, J. Koetz, H. Schlaad
Thermo-induced multistep assembly of double-hydrophilic block copolypeptoids in water
Colloid and Polymer Science 2017, 295, 1305
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 Tcp∼30 and 45 °C and a clearing point in between at Tcl∼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.
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