남재도 교수

Here we introduce the electromagnetic shielding effectiveness (SE) of reduced graphene oxide (RGO) sheets interleaved between polyetherimide (PEI) films fabricated by electrophoretic deposition (EPD). Incorporating only 0.66 vol % of RGO, the developed PEI/RGO composite films exhibited an electromagnetic interference shielding effectiveness (EMI SE) at 6.37 dB corresponding to ∼50% shielding of incident waves. Excellent flexibility and optical transparency up to 62% of visible light was demonstr

Various functional materials, such as metal nanoparticles, carbon nanotubes and conducting polymers were coated on polymer microspheres finding various uses in electronic and biomedical applications. Herein, we demonstrate that single graphene oxide (GO) sheets could be easily wrapped on amine-functionalized poly(glycidyl methacrylate) (PGMA-ed) microspheres (∼2.5 μm in diameter) to form a PGMA-ed/GO core-shell structure with a thickness of ca. 50 nm. Subsequently, the synthesized GO-skin micros

Portable energy storage devices have gained special attention due to the growing demand for portable electronics. Herein, an all-solid-state supercapacitor is successfully fabricated based on a poly(vinyl alcohol)-H3PO4 (PVA-H3PO4) polymer electrolyte and a reduced graphene oxide (RGO) membrane electrode prepared by electrophoretic deposition (EPD). The RGO electrode fabricated by EPD contains an in-plane layer-by-layer alignment and a moderate porosity that accommodate the electrolyte ions. The

A large-area, conductive, and flexible membrane made from the stabilized aqueous solution of reduced graphene oxide (RGO) is successfully fabricated using an electrophoretic deposition (EPD) method. A low-voltage operation of EPD (∼3 volts) allows a robust consolidation of RGO layers desirably aligned in the in-plane direction through the cohesive electrophoretic squeezing force near the current collector. Transferring the deposited RGO layers to arbitrary substrates or achieving as a free-stand

Abstract A composite degradation methodology is extended to the conversion‐dependence function in order to explain the importance of multiple reaction mechanisms which might be considered to be involved in degradation processes. Based on two elementary reaction mechanisms, a specific form of the model equation is derived, which is capable of describing various types of degradation behavior showing sigmoidal rate as well as deceleratory rate. The conversion‐dependence function is derived to be in

As electromagnetic (EM) pollution continues to increase, electromagnetic interference (EMI) shielding materials have been intensively evaluated in terms of two main shielding mechanisms of reflection and absorption. Since the shielding effectiveness (SE) is represented in the logarithmic scale and in a coupled way of transmission (SE_T), absorption (SE_A), and reflection (SE_R), often there is a misinterpretation that the EM wave reflectors are regarded as EM wave-a

Abstract Five different analytical schemes for examining isothermal and nonisothermal degradation of polymers were reviewed and found inadequate for describing multistage decomposition. The different schemes were experimentally tested using thermogravimetric analysis data for an ethylene‐vinyl acetate (EVA) copolymer, which exhibited a well‐behaved two‐step decomposition process in a nitrogen environment. Based on these experimental and analytical findings, a generalized methodology was develope

A new synthesis route of a solution-processed highly conductive self-standing graphite membrane from reassembled graphene oxide (GO) has become one of the intensive research focus, because of its immense application opportunities. Previously demonstrated techniques were limited by the unstable reduced graphene oxide (RGO) dispersion and agglomeration during chemical reduction without any surfactant. This results in poor packing morphology and low electrical conductivity of the RGO membrane. Here