Kyung Hee University · Engineering
Professor Kap Jin Kim's research lab specializes in the development and characterization of piezoelectric and ferroelectric polymers, particularly poly(vinylidene fluoride) (PVDF) and its copolymers, with a focus on enhancing their crystalline phase control and functional properties. The lab investigates the formation of polar β-phase and ferroelectric phases through chemical additives, thermal treatments, and electrospinning techniques to enable applications in flexible nanogenerators, nano-pressure sensors, and wearable biomedical devices. A key research direction involves optimizing the piezoelectric response and polarization behavior for use in energy harvesting and real-time physiological signal monitoring.
Figures are computed from collected data and may differ slightly.
A single stage electrospinning process can give rise to preferentially oriented induced dipoles in poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] nanofibers. The piezoelectricity of as-electrospun P(VDF-TrFE) nanofiber webs opens up new possibilities for their use as a flexible nanogenerators and nano-pressure sensors. In this work, the origin of the piezoelectricity has been spotlighted by randomization of the induced dipoles at the Curie temperature and analyzed by polarized FT-IR s
Abstract The role of organically modified silicate (OMS), Lucentite STN on the formation of β‐crystalline phase of poly(vinylidene fluoride) (PVDF) is investigated in the present study. The OMS was solution blended with PVDF and cast on glass slide to form PVDF‐OMS nanocomposites. Solution cast samples were subjected to various thermal treatments including annealing (AC‐AN), melt‐quenching followed by annealing (MQ‐AN), and melt‐slow cooling (MSC). Fourier‐transform infrared spectroscopy (FT‐IR)
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpectroscopic analysis of the crystalline and amorphous phases in a vinylidene fluoride/trifluoroethylene copolymerKap J. Kim, Nicholas M. Reynolds, and Shaw Ling HsuCite this: Macromolecules 1989, 22, 12, 4395–4401Publication Date (Print):December 1, 1989Publication History Published online1 May 2002Published inissue 1 December 1989https://pubs.acs.org/doi/10.1021/ma00202a001https://doi.org/10.1021/ma00202a001research-articleACS PublicationsRequest re
Abstract In this Communication, the effect of varying mass fractions (0–20 wt.‐%) of calcium chloride (CaCl 2 ) salt on the α ‐ and β ‐phase content of poly(vinylidene fluoride) (PVDF) as‐cast films were investigated. Spectral and X‐ray studies revealed the maximum ferroelectric β ‐phase for the addition of 15 wt.‐% of CaCl 2 in PVDF compared to neat PVDF samples. The dense β ‐phase dominant PVDF–CaCl 2 (15 wt.‐%) thick film used as a ferroelectric insulator in one‐capacitor (1C) type random acc
Abstract We have completely deconvoluted multiple ferroelectric‐to‐paraelectric phase transitions of a VDF/TrFE copolymer often observed on DSC by consecutive annealing below the Curie transition temperature and obtained three clear endothermic peaks resolved well from each other. We could also increase the Curie transition temperature by using the consecutive annealing performed in the ferroelectric state. Annealing time, as well as annealing temperature, was found to affect the Curie transitio
ABSTRACT Human heartbeat and respiration signals were measured from a DAQ board interfaced with a homemade voltage-amplifier with specific frequency filtering function using an elastic textile belt imbedded with a poled-PVDF film, which is designated as a physiological sensing belt (PSB), as a piezoelectric sensor and analyzed. PSB sensor systems can be easily tied on the chest, abdomen, head, wrist, or ankle for comfortable fit. The sensitivity of the imbedded PVDF film sensor is highly depende
Abstract Ultra‐thin films of poly(vinylidene fluoride) (PVDF) and its organically modified silicate (OMS) nanocomposites were prepared by heat‐controlled spin coating and characterized using FTIR‐GIRAS, AFM, DC‐EFM, and P – E measurements. Incorporation of OMS, Lucentite STN into the PVDF matrix favored the preferential formation of β ‐phase in nanoscale thin films, irrespective of preparation temperature. The PVDF–OMS nanocomposite films have a little higher degree of orientation of molecular c
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