Recent developments on the synthesis and flocculation efficiency of several non-ionic, cationic, anionic and amphoteric polymers are presented and summarised.

The synthesis of ultra-high molecular weight (UHMW) polymers using reversible deactivation radical polymerisation techniques remains a challenge and has been the centre of attention only in a limited number of studies. Although UHMW polymers were synthesised in these research studies, the complexity in architecture has mainly been limited to linear homopolymers and AB diblock copolymers. We hereby report a new pathway to synthesise UHMW ABA triblock copolymers using a combination of reversible addition–fragmentation chain transfer (RAFT) polymerisation, end-group modification by aminolysis and chain coupling. A simple aqueous RAFT-mediated gel polymerisation technique was initially employed to synthesise high molecular weight AB diblock copolymers with low dispersities (Đ < 1.50). The use of the said gel polymerisation method in combination with a redox initiation system allowed for the rapid chain propagation of water-soluble monomers at a low reaction temperature of 20 °C. These polymers were subsequently treated by aminolysis to convert the chain end into a thiol functionality, which spontaneously coupled under oxidative conditions to form a disulfide bridge between the AB diblock copolymers to produce the final UHMW ABA triblock copolymers (M_n,SEC > 1000k; Đ < 1.70).

Composite structural supercapacitors (SSC) are an attractive technology for aerospace vehicles; however, maintaining strength whilst adding energy storage to composite structures has been difficult. Here, SSCs were manufactured using aerospace-grade composite materials and CNT mat electrodes. A new design methodology was explored where the supercapacitor electrolyte was localised within the composite structure, achieving good electrochemical performance within the active region, whilst maintaining excellent mechanical performance elsewhere. The morphologies of these localised SSC designs were characterised with synchrotron X-ray fluorescence microscopy and synchrotron X-ray micro-computed tomography and could be directly correlated with both electrochemical and mechanical performance. One configuration used an ionogel with an ionic liquid (IL) electrolyte, which assisted localisation and achieved 2640 mW h kg⁻¹ at 8.37 W kg⁻¹ with a corresponding short beam shear (SBS) strength of 71.5 MPa in the active area. A separate configuration with only IL electrolyte achieved 758 mW h kg⁻¹ at 7.87 W kg⁻¹ with SBS strength of 106 MPa in the active area. Both configurations provide a combined energy and strength superior to results previously reported in the literature for composite SSCs.

Exposure to plasma can significantly increase the surface area of silver species and their resistance to oxidation. While some work investigating plasma-treated silver has been done, limited morphologies and applications have been explored. We hereby explore this effect on silver nanowires (AgNWs) through medium-vacuum air plasma exposure time ranging between 30 s to 60 min. These plasma-treated AgNW networks are directly applied as supercapacitor electrodes, without any carbon or polymer additives that are typically employed alongside silver in energy storage applications. The plasma treatment consequently affected the electrochemical performance of AgNWs, where longer treatment times resulted in higher energy storage capacity. An increase in resistance was observed for plasma treatment times greater than or equal to 5 min, due to the switch from the percolation threshold of the metallic Ag phase to the Ag₂O phase. Despite an initial drop in stored energy, an overall improvement in energy storage capacity was observed throughout cycling, where the optimal plasma treatment time of 5 min resulted in an increase of 320% of its starting value with near 100% coulombic efficiency, through the development of stable redox-active surface nanostructures.