Kim, Doo-Hyun
(Pusan Nationl University, Department of Mechanical Engineering)
,
Hwang, Yu-Jin
(Pusan Nationl University, Department of Mechanical Engineering)
,
Kwon, Yeoung-Hwan
(Pusan Nationl University, Department of Mechanical Engineering)
,
Lee, Jae-Keun
(Pusan Nationl University, Department of Mechanical Engineering)
,
Hong, Dae-Seung
(N-BARO TECH CO)
,
Moon, Seong-Young
(N-BARO TECH CO)
,
Kim, Soo-H.
(Pusan Nationl University, Department of Nanosystem and Nanoprocess Engineering)
The carbon laden suspensions in water with no surfactants have poor stability caused by the hydrophobic layer of particles. In this study, the water-based carbon nano colloide(CNC) was successfully produced using electro-chemical one-step method without agent. The properties of CNC were characterize...
The carbon laden suspensions in water with no surfactants have poor stability caused by the hydrophobic layer of particles. In this study, the water-based carbon nano colloide(CNC) was successfully produced using electro-chemical one-step method without agent. The properties of CNC were characterized by using various techniques such as particle size analyzer, TEM, FT-IR, turbidity meter, viscometer, and transient hot-wire method. The average size of the suspended in the CNC was 15 nm in diameter. The thermal conductivity of CNC compared with water was increased up to 14% with 4.2wt% concentration. The CNC was stable over 600hr. The enhanced colloidal stability of CNC may be caused by the chemical structures, such as, hydroxide and carboxyl groups formed in outer atomic layer of carbon, which (i) made the carbon nanofparticles hydrophilic and (ii) prevented the aggregation among nanoparticles.
The carbon laden suspensions in water with no surfactants have poor stability caused by the hydrophobic layer of particles. In this study, the water-based carbon nano colloide(CNC) was successfully produced using electro-chemical one-step method without agent. The properties of CNC were characterized by using various techniques such as particle size analyzer, TEM, FT-IR, turbidity meter, viscometer, and transient hot-wire method. The average size of the suspended in the CNC was 15 nm in diameter. The thermal conductivity of CNC compared with water was increased up to 14% with 4.2wt% concentration. The CNC was stable over 600hr. The enhanced colloidal stability of CNC may be caused by the chemical structures, such as, hydroxide and carboxyl groups formed in outer atomic layer of carbon, which (i) made the carbon nanofparticles hydrophilic and (ii) prevented the aggregation among nanoparticles.
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가설 설정
8 The schematic of CNC production process in the electrochemical and sonochemical oxidization. (a) van der Waals attraction forces acting between the stacked layers in graphite and (b) functional groups-induced repulsion forces acting between the stacked layer in graphite.
제안 방법
In this paper, we describe an electrochemical and sonochemical oxidation method to produce the water-based carbon nano colloid (CNC) with excellent stability. The morphology and size distribution of CNC prepared in this study was analyzed by using a TEM and a particle sizer..
However, this method is not suitable for our current CNC suspension because the CNC was too dark to detect the volume of sediment. Therefore the supernatant was analyzed in this approach for qualitatively evaluating the stability of CNC suspension by using a turbidity meter. It was observed to be very stable without any abrupt changes in the turbidity values for 600 hours as seen in Fig.
Turbidity analysis was also made to evaluate the colloidal stability of aqueous suspension. To investigate the stabilization mechanism of CNC prepared, FT-IR spectroscopy and zeta potential analysis were made.
With the assistance of a one-step electrochemical oxidization method, the ultra stable aqueous CNC solution was successfully produced without adding any surfactants in this study. Various characterization techniques were employed to measure the physical, chemical, and thermal properties of the CNC by using TEM, particle sizer, FT-IR, zeta meter, transient hot-wire, and viscometer.
이론/모형
The FT-IR spectra were also measured by a Perkin Elmer Spetrum GX spectrometer. Particle size distribution and zeta potential of CNC were measured by a dynamic light scattering and an electrophoretic light scattering (ELS-8000, Otsuka Electronics) technique, respectively. For evaluating the colloidal stability, the turbidity of CNC was measured as a function of sedimentation time with the assistance of nephelometer (2100AN, HACH).
To measure the thermal conductivity of CNC, a transient hot-wire method was employed. Teflon-coated platinum wire with the diameter of 76 ㎛ and the length of 15 cm was used for thermal conductivity measurement based on the hot wire method. The viscosity of CNC was measured by Ubbelohde viscometer (Capillary viscometer with viscoclock, SCHOTT).
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