Amphiphilic Multi‐Arm Star‐Block Copolymers for Encapsulation of Fragrance Molecules

Abstract

Novel amphiphilic multi‐arm star‐block copolymers with a hyperbranched core, a hydrophobic inner shell, and a hydrophilic outer shell have been prepared from a commercial hyperbranched polyester macroinitiator by ring‐opening polymerization of ε‐caprolactone, followed by atom transfer radical polymerization of tert‐butyl acrylate (tBuA). Hydrolysis of the tert‐butyl groups was then used to convert the poly(tBuA) blocks to poly(acrylic acid), resulting in stable amphiphilic core‐shell structures with significantly higher degrees of functionality than reported so far in the literature. A strong correlation between the maximum concentration of selected hydrophobic guest molecules and the concentration of amphiphilic star‐block copolymer in aqueous solution was observed by 1H NMR, demonstrating the capacity of these copolymers to encapsulate and disperse significant loadings (up to about 27 wt.‐%) of volatile hydrophobic molecules such as fragrances in water.magnified image

Folate-conjugated amphiphilic hyperbranched block copolymers based on Boltorn® H40, poly(l-lactide) and poly(ethylene glycol) for tumor-targeted drug delivery

“…So far, several amphiphilic hyperbranched block copolymers have been prepared using H40 as the macroinitiator [9,10]. The synthesis of amphiphilic hyperbranched block copolymer based on a H40 core, a hydrophobic poly(3-caprolactone) inner shell, and a hydrophilic poly (acrylic acid) outer shell has been described for the improved micelle stability and drug loading ability [11]. In another study, water-soluble amphiphilic star block copolymers with a large number of arms were prepared by sequential atom transfer radical polymerization (ATRP) of n-butyl methacrylate and poly(ethylene glycol) methyl ether methacrylate using H40 as the macroinitiator [12].…”

Branched aliphatic polyesters by ring-opening (co)polymerization

“…As was mentioned in the preceding section, materials based on branched poly(ε-caprolactone), polylactide and polyglycolide have been designed as drug carriers [4,27,34,139,140,142,143,146]. Smart medical devices with a shape memory effect have been constructed using branched PCL for polymer network preparation [179].…”

“…In the first step, a linear living polymer, poly(ε-caprolactone) or polylactide (the precursor), was prepared using aluminum isopropoxide A c c e p t e d M a n u s c r i p t 34 The presented strategies lead to branched copolymers with polyester arms emanating from a hyperbranched polyether or polyester core and result in a "core-shell" topology. Such structures, often with amphiphilic character, can be useful as efficient nanocarriers [139,140].…”

“…The other group of macroinitiators that was equally often applied was branched polyesters based on 2,2-bis(hydroxymethyl) propionic acid (bisMPA), obtained by a step process wherein products prepared by statistical polycondensation as well as products with a regular dendrimer structure were used [131][132][133][134][135]139].…”

Water-soluble starlike poly(acrylic acid) graft polymer: preparation and application as templates for silver nanoclusters

“…Nowadays, a wide variety of star polymer architectures with well-defined molecular weights, structural and compositional homogeneity have been prepared due to the development of various controlled polymerization techniques [2,3], such as ring-opening metathesis polymerization [4], anionic polymerization [5], and controlled living radical polymerization [6][7][8][9]. Among these techniques, anionic polymerization is most popularly used to prepare the star polymers with a predetermined arm molar mass.…”