Janus Micelle Formation Induced by Protonation/Deprotonation of Poly(2‐vinylpyridine)‐block‐Poly(ethylene oxide) Diblock Copolymers

Abstract

A novel approach to amphiphilic polymeric Janus micelles based on the protonation/deprotonation process of poly(2‐vinylpyridine)‐block‐poly(ethylene oxide) (P2VP‐b‐PEO) diblock copolymers in THF is presented. It is found that addition of HCl to the micelles solution of P2VP‐b‐PEO copolymers leads to the formation of vesicles. Subsequently mixing a small amount of hydrazine monohydrate with the vesicle solution can induce the dissociation and reorganization of the vesicles into Janus micelles. When HCl is replaced by HAuCl4 precursors, composite Janus particles containing gold in P2VP blocks are obtained.magnified image

Intelligent micellar polymeric nanocarriers for therapeutics and diagnosis

“…Transitions from spherical to other shapes has been observed to be triggered by changes in solvent temperature or polarity or the presence of additives, such as salts or homopolymers, as noted, for example, for nonionic PEO–PPO–PEO . Other more exotic micellar structures, such as core–shell–corona (onionlike), pointed‐oval‐shaped, disk‐shaped, toroidal (doughnutlike), double‐faced (Janus‐type), and bicontinuous BCMs, have also been observed and studied. Although most BCMs designed as drug carriers are spherical, micelles with a more hydrodynamic shape, such as ellipsoidal or disklike ones (mimicking the morphology of natural biological transporters, e.g., erythrocytes), might be more efficient in transporting their cargo through the bloodstream and delivering it to the site of action.…”

“…Nevertheless, a compromise between the chain solubility and micellar core size must be attained by the tuning of the EO and SO block lengths, with an empirical optimal EO–SO ratio found at about 1.5 . Furthermore, the influence of the amount of feeding drug on the encapsulation yield was also largely evidenced …”

Streng zweiphasige weiche und harte Janus‐Strukturen – Synthese, Eigenschaften und Anwendungen

“…Kürzlich wurde die katalytische Aktivität von zweiphasigen TiO 2 /Au-Janus-Nanopartikeln bei der Reduktion von 4-Nitrophenol zu 4-Aminophenol mit Natriumborhydrid nachgewiesen, die zu 99 % Umsetzung innerhalb von 6 min führte. [11] Für die Herstellung von Janus-Strukturen wurden viele Syntheseverfahren entwickelt, wie Selbstorganisation, [12][13][14][15][16][17] Mikrofluidik, [18][19][20] zweiphasiges Jetting, [21][22][23] Alkenmetathese, [24] Protonierungs-Deprotonierungs-Zyklen [25] und andere mehr. [26][27][28][29] Es existieren mehrere Übersichtsartikel, in denen Syntheseverfahren, Eigenschaften und Anwendungen von Janus-Strukturen aus unterschiedlichen Blickwinkeln beschrieben werden.…”

A Simple Route to Asymmetric Composite Particles via Co-assembly of Block Copolymer and Inorganic Nanoparticles in Solution

“…[2] Poly(2-vinylpyridine)-b-poly(ethylene oxide)/Au Janus micelles based on the protonation/deprotonation process of amphiphilic diblock copolymers in THF were prepared. [3] Very recently, a novel approach to organic-inorganic Janus-like particles based on the alkalization process of PS-b-P2VP/FeCl 3 micelles in toluene has also been presented. [4] To date, asymmetric particles embedding superparamagnetic materials have attracted great interest because of their potential applications.…”