We have successfully demonstrated a polymer electrolyte membrane (PEM) composed of core–shell type nanoparticles (NPs) which are silica NPs coated with poly(acrylic acid)- b -polystyrene (PAA- b -PS). In this work, for further improvement of proton conductive performance, we focus on the relationship between the coating amount of PAA and proton conduction performance. The PAA coating amount can be facilely controlled by changing the polymerization conditions. With the optimized PAA coating amount, the proton conductivity shows 9.2 × 10 ⁻⁴ S cm ⁻¹ at 60 °C and 98% relative humidity with low activation energy ( E _a = 0.33 eV). In addition, with coating PS on silica@PAA, silica@PAA- b -PS shows the proton conduction performance in a wide humidity range. It suggests that coated PS prevents the PAA swelling and suppresses flowing moisture out from the membrane. This report indicates that core–shell type NPs show great potential for a good PEM membrane in various operation conditions by simple polymerization conditions.

The proton exchange membrane (PEM) is the main component that determines the performance of polymer electrolyte fuel cells. The construction of proton-conduction channels capable of fast proton conduction is an important topic in PEM research. In this study, we have developed poly(vinylphosphonic acid)-block-polystyrene (PVPA-b-PS)-coated core–shell type silica nanoparticles prepared by in situ polymerization and a core–shell type nanoparticle-filled PEM. In this system, two-dimensional (2D) proton-conduction channels have been constructed between PVPA and the surface of silica nanoparticles, and three-dimensional proton-conduction channels were constructed by connecting these 2D channels by filling with the core–shell type nanoparticles. The proton conductivities and activation energies of pelletized PVPA-coated core–shell type nanoparticles increased depending on the coated PVPA thickness. Additionally, pelletized PVPA-b-PS-coated silica nanoparticles showed a good proton conductivity of 1.3 × 10⁻² S cm⁻¹ at 80 °C and 95% RH. Also, the membrane state achieved 1.8 × 10⁻⁴ S cm⁻¹ in a similar temperature and humidity environment. Although these proton conductivities were lower than those of PVPA, they have advantages such as low activation energy for proton conduction, suppression of swelling due to water absorption, and the ability to handle samples in powder form. Moreover, by using PS simultaneously, we succeeded in improving the stability of proton conductivity against changes in the temperature and humidity environment. Therefore, we have demonstrated a highly durable, tough but still enough high proton conductive material by polymer coating onto the surface of nanoparticles and also succeeded in constructing proton-conduction channels through the easy integration of core–shell type nanoparticles.

Highly luminescent CH ₃ NH ₃ PbBr ₃ perovskite nanocrystals (PeNCs) with a high photoluminescence quantum yield value of 80% are prepared by a forced thin film reactor for continuous production. In this system, the rotating and stationary disks form a confined micro space which demonstrates a unique mixing process through continuous injection of solvents. We found that the unique mixing system leads to colloidal PeNCs with 4 nm–10 nm, which are much smaller than those of a representative T-junction system (15 nm–65 nm). It suggests that a confined micro space is effective for the capping of n-octylamine to the surface of PeNCs, resulting in suppression of the aggregation of the PeNCs and crystal growth. Also, with increasing flow velocity, the optical properties show almost no fluctuation. This system is a promising continuous system to prepare colloidal PeNCs, and can provide a synthetic protocol to be applied for light-emitting diodes as well as various other optoelectronic devices.

Polymer electrolyte membrane (PEM) fuel cells have challenges in operation under low-humidity conditions caused by a proton conduction mechanism dependent on water. We focused on polymeric ionic liquids (PILs), which are promising for high proton conductivity under a wide range of environments because they have the characteristics of polymer electrolyte liquids. However, it is difficult to fabricate self-standing membranes of PILs due to their high hygroscopicity and fluidity. In this paper, to inhibit the fluidity of the PIL in developing a self-standing PEM, the hydrophobic chain segment of styrene is inserted between the PILs of poly(vinylphosphonic acid/1-propylimidazole) (P(VPA/1PIm)) by RAFT polymerization. The synthesized sample of P(VPA/1PIm)-block-polystyrene is potentially applicable to PEM materials because it was obtained in powder state, having a high heat resistance of up to 300 °C, and exhibiting a proton-conducting property under a wide range of environments.

Proton conduction in the current polymer electrolyte membrane depends on water molecules, which necessitates high-humidity environments. On the contrary, proton conduction in low-humidity environments has been required for expanding operation conditions of polymer electrolyte fuel cells. Recently, ionic liquids (ILs) have been focused on novel proton conductive materials, however, the ILs were hard to fabricate the self-standing membrane owing to their fluidity. In this paper, we have developed composite materials composed of ILs and inorganic nanoparticles by coating ILs as polymer states (PILs) on the surface of nanoparticles. Notably, this material has obtained a powder form, and we have succeeded in suppressing the fluidity of ILs. The PILs-coated nanoparticles have achieved good proton conductivity over 10⁻² S cm⁻¹ at 95% RH, also indicated over 10⁻⁴ S cm⁻¹ under 60% RH. In addition, we have clarified the relationship between the thickness of PILs and proton conductivities.