Amphiphilic AB and ABA block copolymers have been demonstrated to form a variety of self-assembled aggregate structures in dilute solutions where the solvent preferentially solvates one of the blocks. The most common structures formed by these amphiphilic macromolecules are spherical micelles, cylindrical micelles and vesicles (polymersomes). Interest into the characterisation and controlled formation of block copolymer aggregates has been spurred on by their potential as surfactants, nano- to micro-sized carriers for active compounds, for the controlled release of encapsulated compounds and for inorganic materials templating, amongst numerous other proposed applications. Research in the past decade has focussed not only on manipulating the properties of aggregates through control of both the chemistry of the constituent polymer blocks but also the external and internal morphology of the aggregates. This review article will present an overview of recent approaches to controlling the self-assembly of amphiphilic block copolymers with a view to obtaining novel micellar morphologies. Whilst the article touches upon multi-compartment micelles particular focus is placed upon control of the overall shape of micelles; i.e. those systems that expand the range of accessible morphologies beyond ‘simple’ spherical and cylindrical micelles namely disk-like, toroidal and bicontinuous micelles.
The detection of stress in polymeric materials such as plastics, elastomers, composites and coatings is critical in the monitoring of material failure including stress fractures, fatigue and hysteresis. Mechanochromic systems that utilise a change in fluorescent output as a result of the mechanical deformation of a polymer have only been actively investigated relatively recently and whilst the field is still relatively small a considerable number of examples of such systems now exist. This article will discuss the principles behind such systems and review examples in the literature and survey the most common fluorophores used in such systems including phenylene vinylene oligomeric derivatives, polycyclic aromatic compounds, carbazole derivatives and conjugated polymers.
18 August 2015 in Journal of Materials Chemistry C
The swelling ratio of a network polydimethylsiloxane correlates with the Hansen solubility parameters, δd, δp and δh and the vapour pressures of organic vapours. The use of PDMS as a mechanical actuator in a prototype wireless RFID passive sensor is demonstrated.
28 October 2008 in Angewandte Chemie International Edition