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Natural single‐chain nanoparticles (SCNPs) such as proteins have inspired research into the formation and application of synthetic SCNPs. Although the latter can mimic general aspects of the self‐assembly behavior of their biological counterparts, these systems remain relatively understudied. In this respect, a systematic series of amphiphilic statistical copolymers (ASC) of different molecular weights, with a hydrophilic comonomer (methacrylic acid) and varying hydrophobic comonomer to encompass methacrylates of different hydrophobicity, are synthesized. Small‐angle X‐ray scattering studies confirmed that SCNPs are achieved for each copolymer series when dispersed in basified water at 1% w/w. When the aggregation number of the ASC nanoparticles is close to unity the particle shape elongates resulting in a larger particle surface area to volume ratio, allowing more hydrophilic groups to locate on the particle surface tending to keep the particle surface charge density (PSC) constant. Thus, within a series, particle elongation increases with copolymer molecular weight. Structural parameters of SCNPs formed by ASCs composed of hydrophobic components with low partition coefficients are well consistent with predictions obtained from the PSC model. These results highlight the main parameters, namely molecular weight and acid content, responsible for the SCNP formation and provide insight into how specific particle morphology can be targeted. [ABSTRACT FROM AUTHOR]

Hydrophilic chitosan (CHT) and hydrophobic polyε‐caprolactone (PCL) are well‐known biocompatible and biodegradable polymers that have many applications in the biomedical and pharmaceutical fields. But the mixtures of these two compounds are considered incompatible, which makes them not very interesting. To avoid this problem and to further extend the properties of these homopolymers, the synthesis of a new graft copolymer, the fully biodegradable amphiphilic poly(ε‐caprolactone‐g‐chitosan) (PCL‐g‐CHT) is described, with an unusual "reverse" structure formed by a PCL backbone with CHT grafts, unlike the "classic" CHT‐g‐PCL structure with a CHT main chain and PCL grafts. This copolymer is prepared via a copper‐catalyzed 1,3‐dipolar Huisgen cycloaddition between propargylated PCL (PCL‐yne) and a new azido‐chitosan (CHT‐N3). In order to obtain an amphiphilic copolymer regardless of the pH, chitosan oligomers, soluble at any pH, are prepared and used. The amphiphilic PCL‐g‐CHT copolymer spontaneously self‐assembles in water into nanomicelles that may incorporate hydrophobic drugs to give novel drug delivery systems. [ABSTRACT FROM AUTHOR]

Biobased amphiphilic diblock copolymers are prepared thanks to the combination of reversible addition–fragmentation transfer (RAFT) polymerization and polymerization‐induced self‐assembly (PISA) in an eco‐friendly solvent mixture. First, the formation of a poly(acrylic acid) macroRAFT agent (PAA‐TTC) is performed in water at 70 °C. Then, in a series of experiments, the PAA‐TTC macroRAFT agent is used directly, without purification, as both chain transfer agent and stabilizing agent in the RAFT‐PISA of menthyl acrylate (MnA) in dispersion in an ethanol/water mixture. The polymerizations of MnA are fast with high final conversions and well‐controlled amphiphilic diblock copolymers are synthesized. Stable, sub‐micrometric spherical particles composed of the diblock copolymers are formed. The influence of the monomer concentration and the length of the solvophobic block on the diameter of the self‐assemblies is studied by means of dynamic light scattering and cryogenic transmission electron‐microscopy. [ABSTRACT FROM AUTHOR]

Poly ((ethylene oxide)- b-(propylene oxide)- b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers ( Mn,total = 6600, 8000, 9150 g·mol−1; Mn,PEO = 2200, 3600, 4750 g·mol−1) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions ( Ð = 1.06-1.08). Surface tension measurements reveal surface-active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid-triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation 'on demand.' [ABSTRACT FROM AUTHOR]

In this paper, a straightforward method to produce poly(3-hydroxyalkanoate)-based multicompartment micelles (MCMs) is presented. Thiol-ene addition is used to graft sequentially perfluorooctyl chains and poly(ethylene glycol) oligomers onto poly(3-hydroxyoctanoate- co-hydroxyundecenoate) oligomers backbone. Well-defined copolymers are obtained as shown by 1H NMR and size-exclusion chromatography. After nanoprecipitation in water, novel PHA-based MCMs are evidenced by cryo-transmission electron microscopy. Moreover, the cytocompatibility of MCMs is demonstrated in vitro via cell viability assay. [ABSTRACT FROM AUTHOR]