Surfactant-free oil/water and bicontinuous microemulsion composed of benzene,ethanol and water

Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel suffactant-free microemulsion（denoted as SFME） composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water（O/W） microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy（FF-TEM） observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.

Scalable nanomanufacturing of surfactant-free carbon nanotube inks for spray coatings with high conductivity

Spray-coated carbon nanotube films offer a simple and printable solution for fabricating low cost, lightweight, and flexible thin-film electronics. However, current nanotube spray inks require either a disruptive surfactant or destructive surface functionalization to stabilize dispersions at the cost of the electrical properties of the deposited film. We demonstrate that high-purity few-walled carbon nanotubes may be stabilized in isopropanol after surface functionalization and that optimizing the ink stability dramatically enhances the conductivity of subsequent spray-coated thin films. We consequently report a surfactant-free carbon nanotube ink for spray-coated thin films with conductivities reaching 2,100 S/cm. Zeta-potential measurements, used to quantify the nanotube ink dispersion quality, directly demonstrate a positive correlation with the spray- coated film conductivity, which is the key metric for high-performance printed electronics.

Fabrication of 3D hollow acorn-shell-like PtBi intermetallics via a surfactant-free pathway for efficient ethylene glycol electrooxidation

The synthesis of atomically ordered Pt-based intermetallic electrocatalysts for the direct alcohol fuel cells generally requires the addition of surfactants or the high-temperature annealing.However,some residual surfactants on the surface of the assynthesized catalysts would prevent the exposure of catalytic active sites,the high-temperature annealing process is easy to accelerate the sintering of the metal,which both lead to the decline of electrocatalytic performance.Herein,we construct the atomically ordered bimetallic PtBi intermetallics with clean surfaces and unique three-dimensional hollow acorn-shell-like structure(3D PtBi HASL)by a simple,low-temperature,surfactant-free one-pot synthetic approach.Benefiting from the special hollow structures,the obtained 3D PtBi HASL intermetallics expose abundant accessible active sites.Moreover,the introduction of oxophilic metal Bi can enhance adsorption of OHads,thereby significantly facilitating removal of poisoned intermediates.Density functional theory(DFT)simulations further indicate that formation of the PtBi intermetallic phase with the downshift of the Pt d-band center endows 3D Pt49.4Bi50.6 HASL intermetallics with significantly attenuated COads and enhanced OHads adsorption,bringing about the boosting electrocatalytic property.The mass activity of the 3D Pt49.4Bi50.6 HASL intermetallics for ethylene glycol oxidation reaction is as high as 24.67 A·mgPt^(−1),which is 12.98 times higher than that of commercial Pt/C(1.90 A·mgPt^(−1)).This work may inspire the design of Pt-based intermetallics as high-efficiency anode electrocatalysts for fuel cell applications.

Tunable gold nanostar synthesis with surfactant-free system

Gold nanoparticle is an important photothermal conversion material in photothermal imaging and photothermal therapy research.There are diverse gold nanoparticles,including gold nanospheres,gold nanorods,gold nanocages,gold nanoshells and gold nanostars.Among them,gold nanostar(AuNS)possesses more excellent prospective imaging contrast agent for cancer diagnosis than other shapes of gold nanoparticles because of its larger photon interception area and cross section as well as scattering characteristics.The properties of AuNS are susceptible to synthetic methods and conditions.In this study,we presented surfactant-free methods to synthesize AuNS,discussed the relationship of AuNS characterization with the synthetic conditions and tested its photothermal effect.The results indicated that length and number of branches in AuNSs were the main factor for absorption wavelength in photothermal conversion,and the Au NSs could be more precisely controlled by changing the synthesis conditions.

Stable controlled growth of 3D CuO/Cu nanoflowers by surfactant-free method for non-enzymatic hydrogen peroxide detection

Sensitive, convenient and rapid detection of hydrogen peroxide（H2 O2） is highly desirable in fields like fundamental biological research, food industries, and clinical environmental analysis. Herein, a hierarchical porous CuO/Cu flower-like active electrode material for non-enzymatic H2 O2 sensor was synthesized via a low-cost and one-step chemical oxidation of Cu powder in water bath without surfactants. In order to discuss the growth mechanism of the product, products with different growth time length were fabricated. The electro-catalysis of all products were first exhibited by cyclic-voltammetry,and the product under 6 h reaction shows the best result. The detailed electro-catalytic behaviors of the best product（under 6 h reaction） are characterized by cyclic-voltammetry and amperometry under alkaline conditions. The materials have high sensitivity of 103 μA mM^（-1） cm^（-2）（R^2= 0.9979）, low detection limit of 2 μmol/L and wide concentration range（from 2 μmol/L to 19.4 mmol/L）. Large specific surface area and stabled nanostructure enabled good features, such as stability and sensitivity for the H2 O2 determination.

A comparison study of the performance of Ag_(2)CO_(3) photocatalysts synthesized respectively in a surfactant-free microemulsion, water, and a water/propan-2-ol mixture

A comparison study was conducted on the performance of the Ag_(2)CO_(3) visible light catalysts synthesized in a surfactant-free microemulsion(SFME),water and water/propan-2-ol mixture,respectively.The XPS spectra show that all the synthesized Ag_(2)CO_(3) products have good purity.The SEM,XRD,BET and DRS characterizations indicate that the Ag_(2)CO_(3) product synthesized in the SFME template has higher crys-tallinity,more regular morphology,more uniform size,larger specific surface area,and stronger visible light absorption performance,thus having better catalytic photodegradation activity for rhodamine B(RhB),methylene blue(MB)and methyl orange(MO).When the degradation time reaches 45 min,the degradation rate of RhB is as high as 99.11%.Na_(2)CO_(3) has a good stabilizing effect when its concentration is 0.001 mol L^(-1).This research is of great significance to expand the application of SFMEs in the synthesis of high-efficiency catalytic materials.

Monodisperse Fe3O4 spheres: Large-scale controlled synthesis in the absence of surfactants and chemical kinetic process

Fe3 O4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering.However,it is highly desired to fully understand the chemical kinetic process and propose a general,surfactantfree,large-scale synthesis approach for Fe3 O4 spheres.Herein,we developed a facile scalable solvothermal method in the absence of surfactants to produce Fe3 O4 spheres with the yield of 5.1 g,which present tunable sizes from 107 to 450 nm by modulated molar ratio of Fe3+/COO-in the solution.Particularly,it is observed that the reactants undergo a redox process,composed of a precipitation-dissolution equilibrium combined with a coordination reaction(termed as RPC),to the final product based on the LaMer model.It is worth noting that the generation of di-carboxyl group and its coordination with iron cations determine the formation of Fe3 O4 spheres.This work not only offers a strategy to precisely tailor the particle size in scalable synthesis process,but also gives the insight on the role of dihydric alcohol in the formation mechanism of Fe3 O4 spheres in the absence of surfactants.

INTERACTION OF ANTIGEN AND ANTIBODY ON CORE-SHELL POLYMERIC MICROSPHERES

Monodispersed microspheres with polystyrene as the core and poly（acrylamide-co-N-acryloxysuccinirnide） as the shell were synthesized by a two-step surfactant-free emulsion copolymerization.The core-shell morphology of the microspheres was shown by scanning electron microscopy and transmission electron microscopy.Rabbit immunoglobulin G （as antigen） was covalently coupled onto the microspheres by the reaction between succinimide-activated ester groups on the shell of the microspheres and amino groups of the antigen molecules.The size of particles was characterized by dynamic light scattering technique and was found to vary upon bioconjugation and interaction with proteins.The binding process was shown to be specific to goat anti-rabbit immunoglobulin G（as antibody） and reversible upon the addition of free antigen into the system.