Photoresponsive complex emulsions are prepared in a three-phase system consisting of two oils: hexane (H) and perfluorooctane (F). An aqueous solution of a mixed surfactant of fluorosurfactant, F(CF) (CHCHO) H (Zonyl FS-300), and a synthesized light-responsive surfactant, 2-(4-(4-butylphenyl)diazenylphenoxy)ethyltrimethylammonium bromide (CAZOCTAB) was employed as the continuous phase. Complex emulsions with various geometries were prepared by one-step vortex mixing and a temperature-induced phase-separation method. It was noticed that the topology of the complex emulsion was highly dependent on the mass ratio of Zonyl FS-300/CAZOCTAB. Light microscopy images showed that phase inversion from an H/F/W- to an F/H/W-type double emulsion via a Janus emulsion was achieved by gradually increasing the mass ratio of CAZOCTAB/Zonyl FS-300. Upon UV/blue light irradiation, the topology of complex emulsions was turned to switch from an F/H/W double emulsion to a Janus emulsion to an entirely inverted H/F/W double emulsion. Dynamic interfacial tension measurements showed that UV irradiation of the interface between an aqueous trans-CAZOCTAB solution and hexane brings about an increase in the interfacial tension, suggesting the nature of photoinduced morphological changes in complex emulsions. The reconfiguration process of complex emulsions was illustrated by the Marangoni effect based on heterogeneity in the interfacial tension at the complex emulsion surface induced by controlling the molecular conversion of CAZOCTAB using light irradiation. Finally, we used the complex emulsions structure to form an on-off switch to start and shut off the evaporation of one volatile phase to achieve process monitoring. This could be used to initiate and quench a reaction, which offers a novel idea for achieving switchable and reversible reaction control in multiple-phase reactions.

A novel MOF-derived MnCoOx nanoparticles embedded in porous N-doped carbon catalyst exhibits excellent catalytic activity for the low-temperature oxidation of formaldehyde.

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In this work, polyamide 6 (PA6) composites with improved flame retardancy and thermal conductivity were prepared with different thermal conductive fillers (TC fillers) such as aluminum nitride (AlN) and boron nitride (BN) in a PA6 matrix with aluminum diethylphosphinate (AlPi) as a fire retardant. The resultant halogen-free flame retardant (HFFR) and thermal conductive (TC) PA6 (HFFR-TC-PA6) were investigated in detail with a mechanical property test, a limiting oxygen index (LOI), the vertical burning test (UL-94), a cone calorimeter, a thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology of the impact fracture surface and char residue of the composites were analyzed by scanning electron microscopy (SEM). It was found that the thermal conductivity of the HFFR-TC-PA6 composite increased with the amount of TC fillers. The TC fillers exerted a positive effect for flame retardant PA6. For example, the HFFR-TC-PA6 composites with the thickness of 1.6 mm successfully passed the UL-94 V-0 rating with an LOI of more than 29% when the loading amount of AlN-550RFS, BN-SW08 and BN-NW04 was 30 wt%. The morphological structures of the char residues revealed that TC fillers formed a highly integrated char layer surface (without holes) during the combustion process, as compared to that of flame retardant PA6/AlPi composites. In addition, the thermal stability and crystallization behavior of the composites were studied.