Temperature and solvent isotope dependent hierarchical self-assembly of a heterografted block copolymer

Abstract

Push reversible transitions to the limit! Upon heating, 6–8 kinds of distinct nano-object morphologies can be achieved by H2O/D2O-mediated hierarchical self-assembly.

Stereocomplex Polylactide for Drug Delivery and Biomedical Applications: A Review

“…Non-covalent interactions, such as electrostatic interactions, hydrogen bonding, and hydrophobic-hydrophobic interactions are driving forces to induce self-assembly of amphiphilic block copolymers. The stability of the self-assembly can be influenced by several environmental factors, including the pH, temperature, polymer concentration, and ionic strength [ 22 , 23 , 24 , 25 ]. Bishara et al synthesized stereocomplex particles composed of an enantiomeric triblock copolymer (PLA-PEG 2000 -PLA) by blending in acetonitrile solutions [ 26 ].…”

Multi-tunable aggregation behaviors of thermo/pH-responsive toothbrush-like and jellyfish-like copolymers

“…[46][47][48] In addition, the rational design of stimuli-responsive polymers allows the formation of hierarchical nanostructures involving spheres (S), vesicles (V), cylinders, disks and lamellae (L), and sequential morphological transitions can occur under external stimuli. Thermoinduced self-assembly (TISA) of thermoresponsive copolymers results in sphere-worm-vesicle-lamella (for linear diblock copolymer), 49 sphere-vesicle-lamella-vesicle (for linear copolymer bearing Y junctions), 15 sphere-nanobowl-vesicle-disklamella-branched micelle (for heterografted copolymer), 50 and sphere-lamella-disk as well as lamella-vesicle-disk-like vesicle (for toothbrush-like terpolymer) 51 transitions. During pHinduced self-assembly ( pHISA) of pH-sensitive copolymers, sphere-disk-vesicle-disk-like vesicle-lamella (for toothbrushlike terpolymer), 51 cylinder-lamella-vesicle-sphere (for star terpolymer), 52 and dendritic vesicle-vesicle-lamella-tadpolemicellar cluster (for tadpole-linear terpolymer) 52 transitions are noted.…”

“…Despite the tremendous progress in hierarchical self-assembly, reports on a single thermo/pH-responsive polymer to achieve four or more kinds of distinct nanostructures have been relatively scarce. 15,[49][50][51][52] At present, it is timely to rationally design architectural polymers to attain this goal.…”

“…Rational macromolecular design holds great promise in addressing the challenge in facile fabrication of multiply transformable nano-objects with distinct shapes and dimensions. As far as PNIPAM (A) and PDMAEMA (B) bearing polymers with stimuli-tunable morphological transitions are concerned, we have designed a heterografted triblock copolymer 50 and a (AB) m C-type (C = poly(N,N-dimethylacrylamide)) heterografted toothbrush-like terpolymer 51 to sequentially form at least four types of nano-objects in water via TISA and pHISA. To achieve these hierarchical nanostructures, is it possible to further simplify the model polymer to a bicomponent diblock copolymer comprising A and B?…”

“…Moreover, the utilization of thermo-and pHresponsive segments makes it possible to tune chain conformations, hydrophobic fraction and mutual interactions upon application of external stimuli. 15,27,[41][42][43][44][45][46][47][48][49][50][51][52] These factors further drive the reassembly of copolymer assemblies until thermodynamic equilibrium is reached. During destabilization and reaggregation, various nano-objects such as spheres, vesicles, lamellae and porous lamellae (PL) may be formed and fixed by adopting suitable topology, composition and stimuli.…”