The co-assembly of ionic-neutral block copolymers with oppositely charged species produces nanometric colloidal complexes, known, among other names, as complex coacervates core micelles (C3Ms). C3Ms are of widespread interest in nanomedicine for controlled delivery and release, whilst research activity into other application areas, such as gelation, catalysis, nanoparticle synthesis, and sensing, is increasing. In this review, we discuss recent studies on the functional roles that C3Ms can fulfil in these and other fields, focusing on emerging structure–function relations and remaining knowledge gaps.
Electrostatically
coassembled micelles constitute a versatile class
of functional soft materials with broad application potential as,
for example, encapsulation agents for nanomedicine and nanoreactors
for gels and inorganic particles. The nanostructures that form upon
the mixing of selected oppositely charged (block co)polymers and other
ionic species greatly depend on the chemical structure and physicochemical
properties of the micellar building blocks, such as charge density,
block length (ratio), and hydrophobicity. Nearly three decades of
research since the introduction of this new class of polymer micelles
shed significant light on the structure and properties of the steady-state
association colloids. Dynamics and out-of-equilibrium processes, such
as (dis)assembly pathways, exchange kinetics of the micellar constituents,
and reaction-assembly networks, have steadily gained more attention.
We foresee that the broadened scope will contribute toward the design
and preparation of otherwise unattainable structures with emergent
functionalities and properties. This Viewpoint focuses on current
efforts to study such dynamic and out-of-equilibrium processes with
greater spatiotemporal detail. We highlight different approaches and
discuss how they reveal and rationalize similarities and differences
in the behavior of mixed micelles prepared under various conditions
and from different polymeric building blocks.
Self-assembly of block copolymers in solution is a topic of great interest in polymer science due to the potential for applications as a drug carrier system. In bulk, fully discrete...
Carbon nanofibers (CNFs) with high surface area (820 m/g) have been successfully prepared by a nanocasting approach using silica nanofibers obtained from chromonic liquid crystals as a template. CNFs with randomly oriented graphitic layers show outstanding electrochemical supercapacitance performance, exhibiting a specific capacitance of 327 F/g at a scan rate of 5 mV/s with a long life-cycling capability. Approximately 95% capacitance retention is observed after 1000 charge-discharge cycles. Furthermore, about 80% of capacitance is retained at higher scan rates (up to 500 mV/s) and current densities (from 1 to 10 A/g). The high capacitance of CNFs comes from their porous structure, high pore volume, and electrolyte-accessible high surface area. CNFs with ordered graphitic layers were also obtained upon heat treatment at high temperatures (>1500 °C). Although it is expected that these graphitic CNFs have increased electrical conductivity, in the present case, they exhibited lower capacitance values due to a loss in surface area during thermal treatment. High-surface-area CNFs can be used in sensing applications; in particular, they showed selective differential adsorption of volatile organic compounds such as pyridine and toluene. This behavior is attributed to the free diffusion of these volatile aromatic molecules into the pores of CNFs accompanied by interactions with sp carbon structures and other chemical groups on the surface of the fibers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.