Abstract
AbstractThe thermoresponsive behavior of a poly(2-oxazoline)-based molecular brush is investigated in aqueous solution. The molecular brush under study, PiPOx100-g-PEtOx17, has a poly(2-isopropenyl-2-oxazoline) (PiPOx) backbone grafted with thermoresponsive poly(2-ethyl-2-oxazoline) (PEtOx) side chains. Since the backbone degree of polymerization is only a factor of ~ 6 higher than the ones of the side chains, it features an architecture between a star-like polymer and a comb-like polymer. Its aqueous solution exhibits lower critical solution temperature (LCST) behavior with a cloud point temperature Tcp = 40.5 °C at 30 g L−1. The temperature-dependent structural evolution is disclosed using dynamic light scattering (DLS) and small-angle neutron scattering (SANS). An increase of the molecular brush size is found upon heating from room temperature to Tcp, which is attributed to the extension of the backbone resulting from the dehydration and collapse of the side chains. Above Tcp, the size decreases again, which indicates the collapse of the whole molecular brush. Large aggregates are found to be present in the solution in the temperature range 25–50 °C. These become more compact, as the temperature is increased across Tcp.
Funder
Master in Materials Science Exploring Large Scale Facilities
Deutsche Forschungsgemeinschaft
Publisher
Springer Science and Business Media LLC
Subject
Materials Chemistry,Colloid and Surface Chemistry,Polymers and Plastics,Physical and Theoretical Chemistry
Reference52 articles.
1. Yuan J, Müller AHE, Matyjaszewski K, Sheiko SS (2012) 6.06 - molecular brushes. In: Matyjaszewski K, Möller M (eds) Polymer science: a comprehensive reference. Elsevier, Amsterdam
2. Verduzco R, Li X, Pesek SL, Stein GE (2015) Structure, function, self-assembly, and applications of bottlebrush copolymers. Chem Soc Rev 44(8):2405–2420
3. Johnson JA, Lu YY, Burts AO, Xia Y, Durrell AC, Tirrell DA, Grubbs RH (2010) Drug-loaded, bivalent-bottle-brush polymers by graft-through ROMP. Macromolecules 43(24):10326–10335
4. Miki K, Kimura A, Oride K, Kuramochi Y, Matsuoka H, Harada H, Hiraoka M, Ohe K (2011) High-contrast fluorescence imaging of tumors in vivo using nanoparticles of amphiphilic brush-like copolymers produced by ROMP. Angew Chem Int Ed 50(29):6567–6570
5. Miyake GM, Weitekamp RA, Piunova VA, Grubbs RH (2012) Synthesis of isocyanate-based brush block copolymers and their rapid self-assembly to infrared-reflecting photonic crystals. J Am Chem Soc 134(34):14249–14254
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