A5073787901- Advanced Polymer Synthesis and Characterization
- Block Copolymer Self-Assembly
- Electrospun Nanofibers in Biomedical Applications
- Polymer Surface Interaction Studies
- Advanced Sensor and Energy Harvesting Materials
- Graphene research and applications
- Conducting polymers and applications
- Electrohydrodynamics and Fluid Dynamics
- Material Dynamics and Properties
- Wound Healing and Treatments
- Carbon Nanotubes in Composites
- Advancements in Photolithography Techniques
- Synthesis and properties of polymers
- Supercapacitor Materials and Fabrication
- Photopolymerization techniques and applications
- Gas Sensing Nanomaterials and Sensors
- Organic Electronics and Photovoltaics
- Machine Learning in Materials Science
- biodegradable polymer synthesis and properties
- Surface Modification and Superhydrophobicity
- Polymer composites and self-healing
- Molecular Junctions and Nanostructures
- Nanofabrication and Lithography Techniques
- Hydrogels: synthesis, properties, applications
- Force Microscopy Techniques and Applications
Inha University
2015-2024
Incheon National University
2018
Incheon Medical Center
2017-2018
Government of the Republic of Korea
2018
Sungkyunkwan University
2018
Cornell University
2017
Ithaca College
2017
University of Wisconsin–Madison
2010-2015
Hanyang University
2003-2006
We demonstrate the fabrication of nanoperforated graphene materials with sub-20-nm features using cylinder-forming diblock copolymer templates across >1 mm2 areas. Hexagonal arrays holes are etched into membranes, and remaining constrictions between interconnect forming a honeycomb structure. Quantum confinement, disorder, localization effects modulate electronic structure, opening an effective energy gap 100 meV in nanopatterned material. The field-effect conductivity can be modulated by...
We report a route to noncovalently latch dipolar molecules on graphene create stable chromophore/graphene hybrids where molecular transformation can be used as an additional handle reversibly modulate doping while retaining high mobilities. A light switchable azobenzene chromophore was tethered the surface of via π-π interactions, leading p-doping with hole concentration ~5 × 10(12) cm(-2). As switch from trans cis form dipole moment changes, and hence extent doping, resulting in modulation...
In this review, we describe the latest advances in synthesis, characterization, and applications of polymer brushes. Synthetic towards well-defined brushes, which meet criteria such as: (i) Efficient fast grafting, (ii) Applicability on a wide range substrates; (iii) Precise control surface initiator concentration hence, chain density are discussed. On characterization end methods for determination relevant physical parameters as grafting The impact these specifically emerging fields nano-...
Abstract Interest in wearable and stretchable on‐skin motion sensors has grown rapidly recent years. To expand their applicability, the sensing element must accurately detect external stimuli; however, weak adhesiveness of sensor to a target object been major challenge developing such practical versatile devices. In this study, freestanding, stretchable, self‐adhesive ionogel conductors are demonstrated which composed an associating polymer network ionic liquid that enable conformal contact...
The application of engineered biomaterials for wound healing has been pursued since the beginning tissue engineering. Here, we attempt to apply functionalized lignin confer antioxidation extracellular microenvironments wounds and deliver oxygen from dissociation calcium peroxide enhanced vascularization responses without eliciting inflammatory responses. Elemental analysis showed 17 times higher quantity in oxygen-releasing nanoparticles. Lignin composites including oxygen-generating...
A novel approach for the rational synthesis of low-defect density, patterned graphene from bottom up, called barrier-guided chemical vapor deposition, is introduced. barrier layer impedes growth in selected areas copper substrate, guiding into desired micro- and nano- structures with control over placement, orientation, spatial lateral extent.
Thin film fabrication is necessary to realize the device integration of organic–inorganic hybrid perovskites (OIHPs), and solution-based crystallization methods have been employed widely this end. Despite versatility solution approach, using typical "top-down" lithography generally incompatible with as-prepared OIHPs films because low stability polar solvents involved in lithographic process. Moreover, solution-prepared usually exhibit irregular surface roughness, implying existence randomly...
A series of poly(4-tert-butylstyrene-block-2-vinylpyridine) [P(tBuSt-b-2VP)] block copolymers (BCPs) with varying volume fractions, molecular weights, and narrow dispersities were synthesized from the commercially available monomers by sequential living anionic polymerization. The thoroughly characterized 1H NMR spectroscopy, size exclusion chromatography, thermal gravimetric analysis, differential scanning calorimetry (DSC). To examine effect tert-butyl group on effective interaction...
We demonstrate the modulation of physical and mechanical properties by controlling crystallinity in cross-linked poly(vinyl alcohol) (PVA) nanofibers using a simple straightforward freezing/thawing process.
Deposition of block copolymer thin films is most often accomplished in a serial process where material spin coated onto substrate and subsequently annealed, either thermally or by solvent vapor, to produce well-ordered morphology. Here we show that under appropriate conditions, may be continuously grown equilibrated conditions slow deposition discrete subattoliter quantities using electrospray. We conduct time-resolved observations investigate the effects parameters underpin film morphology...
We demonstrate the fabrication and study of structure–property relationships large-area (>1 cm2) semiconducting nanoperforated (NP) graphene with tunable constriction width (w = 7.5–14 nm), derived from CVD using block copolymer lithography. Size-tunable constrictions were created while minimizing unintentional doping by a dual buffer layer pattern-transfer method. An easily removable polymeric was sandwiched between an overlying silicon oxide underlying graphene. Perforation-size controlled...
We describe the morphological implications of broad molecular weight dispersity on bulk and thin film self-assembly behavior seven model poly(styrene-block-methyl methacrylate) (SM) diblock copolymers. Derived from sequential nitroxide-mediated polymerizations, these unimodal copolymers are comprised narrow S blocks (Đ ≤ 1.14) M ∼ 1.7) with total weights Mn,total = 29.2–42.9 kg/mol volume fractions fM 0.35–0.63. Small-angle X-ray scattering (SAXS) transmission electron microscopy (TEM)...
Electrospraying is an effective and facile technique for the production of micro- or nanoparticles with tailored sizes, shapes, morphologies, microstructures. We synthesized functionalizable poly(styrene-random-glycidyl methacrylate) copolymers used them to fabricate microparticles via electrospray technique. The sizes morphologies electrosprayed particles are controlled by altering process parameters (feed rate applied voltage), composition thermodynamic properties polymer (i.e.,...
The effective approach for coloration and chromatic sensing of electrospun cellulose fabrics with a natural colorant, curcumin, is demonstrated. To achieve high surface area, the morphology fiber was controlled to have rough porous through an electrospinning acetate (CA) solution under optimized parameters solvent system. resulting CA fibers were treated curcumin dye/NaOH ethanol solution, in which deacetylation high-quality simultaneously achieved. As control, cotton similar diameter smooth...
We have synthesized a series of poly(4-(2-tetrahydropyranyloxy)styrene) [P(OTHPSt)] homopolymers by living anionic polymerization the protected monomer (OTHPSt) in tetrahydrofuran at −78 °C, with excellent control over molecular weight and dispersity. The high Tg P(OTHPSt) led to facile purification isolation polymer as powder. Characterization POTHPSt homopolymer nuclear Overhauser effect spectroscopy confirms strong preference for axial position relatively sterically demanding alkoxy...
Recently, single-walled carbon nanotubes as well graphene functionalized with azobenzene chromophores have drawn attention for applications in optoelectronics due to their ability undergo cis–trans isomerization when exposed light. The electronic properties of the nanocarbon materials at these unconventional interfaces can be tailored by gaining structural insight into organic monolayers molecular level. In this work, we use polarization-dependent X-ray absorption spectroscopy probe...
Graphene-enhanced Raman scattering (GERS) is a promising characterization technique which uses single layer of graphene. As the electronic coupling adsorbates with graphene leads to enhancement in signal, it immense interest explore factors that affect To probe this effect we have designed and synthesized series dipolar molecules general structure, N-ethyl-N-(2-ethyl(1-pyrenebutyrate)-4-(4-R-phenylazo)aniline) where R-groups are varied from methoxy (−OCH3), methyl (−CH3), hydrogen (−H),...
Tungsten trioxide (WO<sub>3</sub>) based nanofibers have many advantages as photocatalysts due to its band gap which fits with readily accessible light sources.