Solution self-assembly of fluorinated polymers, an overview

The incorporation of fluorinated moieties into a polymer can confer unique properties and often lead in solution to original morphologies endowed with rare properties.

A unique 19F MRI agent for the tracking of non phagocytic cells in vivo

There is currently intense interest in new methods for understanding the fate of therapeutically-relevant cells, such as mesenchymal stem cells (MSCs). The absence of a confounding background signal and consequent unequivocal assignment makes 19F MRI one of the most attractive modalities for the tracking of injected cells in vivo. We describe here the synthesis of novel partly-fluorinated polymeric nanoparticles with small size and high fluorine content as MRI agents. The polymers, constructed from perfluoropolyether methacrylate (PFPEMA) and oligo(ethylene glycol) methacrylate (OEGMA) have favourable cell uptake profiles and excellent MRI performance. To facilitate cell studies the polymer was further conjugated with a fluorescent dye creating a dual-modal imaging agent. The efficacy of labelling of MSCs was assessed using 19F NMR, flow cytometry and confocal microscopy. The labelling efficiency of 2.6 ± 0.1 × 1012 19F atoms per cell, and viability of >90% demonstrates high uptake and good tolerance by the cells. This loading translates to a minimum 19F MRI detection sensitivity of ∼7.4 × 103 cells per voxel. Importantly, preliminary in vivo data demonstrate that labelled cells can be readily detected within a short acquisition scan period (12 minutes). Hence, these copolymers show outstanding potential for 19F MRI cellular tracking and for quantification of non-phagocytic and therapeutically-relevant cells in vivo.

Combined use of breath figures process and microphase separation of PS-b-P4VP to produce stable porous nanomaterials

Among various templating strategies available for the preparation of porous polymer films, Breath Figures (BFs) as a fast, low-cost and versatile method has aroused extensive interest.

Star Polymers

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

Highly Ordered Honeycomb Film Formation of Linear Polymers by the Breath Figure Technique

Highly ordered, porous honeycomb (HC) films were prepared by the breath figure technique from linear polymers poly(methyl methacrylate) (PMMA) and polystyrene (PS). Typically HC films are difficult to form from such simple linear polymers. The addition of a novel fluorinated polymer (FP) additive with as little as 1 wt-% to PMMA or 5 wt-% to PS was required to obtain regular porous HC films. Through investigation of the influence of the additive on the polymer properties, three parameters based on interfacial tension, polymer solution viscosity, and polymer solidification rate were identified as key factors affecting the ability of polymer systems to form regular porous HC films. A new hypothesis was subsequently developed based on the relationships of these parameters to explain the unusual behaviour associated with HC film formation from linear PMMA and PS with addition of FP additive. This work will provide a new tool to guide the formation of HC films and will greatly broaden the range of polymers used to form HC films in the future.

Multiple interfaces in self-assembled breath figures

Progress in the breath figure method is reviewed by emphasizing the role of the multiple interfaces and the applications of honeycomb films in separation, biocatalysis, biosensing, templating, stimuli-responsive surfaces and adhesive surfaces.

Azobenzene-Functionalised Core Cross-Linked Star Polymers and their Host–Guest Interactions

Water-soluble poly(2-hydroxyethyl acrylate) (PHEA)-based core cross-linked star polymers were efficiently synthesised with high macroinitiator-to-star-conversion (>95 %) in a one-pot system via single electron transfer-living radical polymerisation. The star polymers display excellent water solubility and the pendant hydroxyl groups provide a platform for facile post-functionalisation with various molecules. In demonstrating this, a photo-isomerisable molecule, 4-(phenylazo)benzoic acid was conjugated onto the preformed stars through partial esterification of the available hydroxyl groups (5–20 %). The azobenzene functionalised stars were subsequently employed to form reversible inclusion complexes with α-cyclodextrin.