Kyung Hee University · Materials Science
Professor Jeewoo Lim's research lab specializes in the development of advanced sulfur-based polymers and high-refractive-index materials for optoelectronic and energy storage applications. The lab focuses on innovative chemical processes such as inverse vulcanization and sulfur chemical vapor deposition (sCVD) to transform elemental sulfur—a low-cost, abundant byproduct—into functional materials with tunable optical, thermal, and mechanical properties. Key research directions include the design of high-refractive-index polymers for optical devices, sulfur-rich materials for secondary batteries, and thermally stable, processable polymers for flexible electronics.
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Elemental sulfur is an abundant and inexpensive material obtained as a by-product of natural-gas and petroleum refining operations. Recently, the need for the development of new energy-storage systems brought into light the potential of sulfur as a high-capacity cathode material in secondary batteries. Sulfur-containing materials were also shown to have useful IR optical properties. These developments coupled with growing environmental concerns related to the global production of excess elementa
High refractive index polymers (HRIPs) have recently emerged as an important class of materials for use in a variety of optoelectronic devices including image sensors, lithography, and light-emitting diodes. However, achieving polymers having refractive index exceeding 1.8 while maintaining full transparency in the visible range still remains formidably challenging. Here, we present a unique one-step vapor-phase process, termed sulfur chemical vapor deposition, to generate highly stable, ultrahi
High-refractive-index sulfur-rich polymers with significantly improved thermal properties are prepared using divinylbenzene (DVB) as a comonomer in a modified, low-temperature inverse vulcanization with elemental sulfur. Differential scanning calorimetry and Fourier transform infrared studies reveal that under the modified inverse vulcanization conditions, homopolymerized DVB segments form, leading to high glass-transition temperatures (<i>T</i><sub>g</sub> > 100 °C) and thermal stability previo
Inverse vulcanization provides a simple, solvent-free method for the preparation of high sulfur content polymers using elemental sulfur, a byproduct of refining processes, as feedstock. Despite the successful demonstration of sulfur polymers from inverse vulcanization in optical, electrochemical, and self-healing applications, the mechanical properties of these materials have remained limited. We herein report a one-step inverse vulcanization using allyl glycidyl ether, a heterobifunctional como
High refractive index (RI) thin films are of critical importance for advanced optical devices, and the high refractive index polymers (HRIPs) constitute an interesting class of materials for high RI thin films due to low cost, good processability, light weight, and high flexibility. However, HRIPs have yet to realize their full potential in high RI thin film applications due to their relatively low RI, strong absorption in the blue light region, and limited film formation methods such as rapid v
It's just a phase: A highly fluorinated compound with a rigid three-dimensional architecture was synthesized as a monomer for poly(p-phenyleneethynylene)s (PPEs). Fluorous biphase reactions were applied for the synthesis of a PPE that is soluble only in fluorous solvents. A fluorous solution of the polymer could be processed into aqueous emulsions that display high fluorescence quantum yields (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Informati
Abstract Elementarer Schwefel ist ein weitverbreitetes und preiswertes Material, das bei der Erdgas‐ und Erdöl‐Raffination als Nebenprodukt anfällt. Die Notwendigkeit, neue Energiespeichersysteme zu entwickeln, brachte vor kurzem das Potential von Schwefel als hochleistungsfähiges Kathodenmaterial in Sekundärbatterien ans Licht. Außerdem wurden die nützlichen optischen Eigenschaften schwefelhaltiger Materialien im Infrarotbereich entdeckt. Diese Entwicklungen gepaart mit den wachsenden ökologisc
We herein report the preparation of high refractive index polymers (HRIPs) with enhanced thermal stability from the copolymerization of S8 and divinylbenzene (DVB) in a single step through sulfur chemical vapor deposition (sCVD). Varying the process temperature in sCVD allowed for the preparation of a series of high sulfur content polymers which, in comparison to previously reported sulfur-derived polymers with similar compositions, displayed significantly enhanced solvent resistance, glass tran
Thiol-functionalized polymer nanoparticles demonstrated well-defined mercury ion uptake kinetics, along with a very high mercury ion capture capacity.
Sulfur-rich materials have recently attracted keen interest for their potentials in optical, electrochemical, and pesticidal applications as well as their utility in dynamic covalent bond chemistry. Many sulfur-rich polymers, however, are insoluble and processing methods are therefore very limited. The synthesis and characterization of water-dispersible polymer nanoparticles (NPs) with the sulfur content exceeding 75% by weight, obtained from the interfacial polymerization between 1,2,3-trichlor
A one-pot synthesis of sulfur-rich polymer nanoparticles through a ring-opening metathesis polymerization is reported. The nanoparticles are formed in situ from diblock copolymers containing a polynorbornene derivative bearing cyclic polysulfanes. The refractive indices of the resulting nanoparticles are readily controlled in the range from 1.54 to nearly 1.65.
A high-index thermoset was prepared under thiol-free conditions where the refractive index can be controlled over the range of 1.70–1.75.
Emission wavelength control in fluorescent nanoparticles (NPs) is crucial for their applications. In the case of inorganic quantum dots or dye-impregnated silica NPs, such a control is readily achieved by changing the size of the particles or choosing appropriate fluorescent dyes, respectively. A similar modular approach for controlling the emission wavelength of fluo-rescent polymer NPs, however, is difficult. This article reports on fluorescent polymer NPs, the synthesis of which provides a pl
High sulfur content polymers (HSCPs) are regarded as promising materials for infrared (IR) optics, especially the long-wave IR range, due to intrinsic properties of sulfur, but the poor thermal stability of HSCPs limits their reliable utilization in wider IR applications. We herein present a new HSCP, poly(sulfur-co-hexavinyl disiloxane) (pSHVDS), prepared directly from elemental sulfur through sulfur vapor chemical deposition (sCVD). By employing hexavinyl disiloxane (HVDS) comonomer with high
Synthesis of fluorinated polynorbornene BCPs and swelling-induced pore generation of their films using fluorous solvent.
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