http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Dual Nanopatterns Consisting of Both Nanodots and Nanoholes on a Single Substrate
Choi, Chungryong,Go, Myeongcheol,Park, So Yeong,Kang, Sukwon,Seo, Yeseong,Lee, Jaeyong,Kim, Jin Kon American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.47
<P>Block copolymers (BCPs) with various nanostructures such as spheres, cylinders, gyroid, and lamellae, have received great attention for their application in nanolithography through nanopattern transfer to substrates. However, the fabrication of diverse geometries, shapes and sizes of nanostructure on a single substrate at the desired position could not be achieved because the nanostructure based on BCPs is mainly determined by the volume fraction of one block. Here, we synthesize polystyrene-<I>hv</I>-poly(methyl methacrylate) copolymer (PS-<I>hv</I>-PMMA), which contains a photocleavable linker at the junction point between PS and PMMA blocks. After vertically oriented PMMA cylindrical nanodomains in a thin film on a substrate were obtained, dual nanopatterns composed of high-density array of nanodots and nanoholes were successfully fabricated at the desired area on a single substrate using selective irradiation with a mask. The dual nanopatterns could be used to prepare metal (or metal oxide) nanostructure arrays consisting of both nanodots and nanoholes, which are utilized for smart sensors capable of simultaneously detecting two independent molecules on nanodots and nanoholes.</P> [FIG OMISSION]</BR>
Microphase Separation of P3HT-Containing Miktoarm Star Copolymers
Park, Jicheol,Choi, Chungryong,Hyun, Seung,Moon, Hong Chul,Vincent Joseph, Kanniyambatti L.,Kim, Jin Kon American Chemical Society 2016 Macromolecules Vol.49 No.2
<P>Well-defined [poly(methyl methacrylate)](2)poly(3-hexylthiophene) miktoarm star copolymers (PMMA(2)P3HT) were successfully synthesized via anionic coupling reaction. P3HT with two bromine groups at one chain end (P3HT-Br-2) was synthesized by Williamson reaction between excess amount of tris(bromomethyl)benzene and hydroxyl-terminated P3HT. From anionic coupling reaction between living PMMA anions and P3HT-Br-2, we prepared a series of PMMA(2)P3HTs having narrow molecular weight distribution (polydispersity index < 1.21) with various block compositions. While most P3HT-containing linear rod-coil block copolymers show only fibril structure, PMMA(2)P3HT shows conventional block copolymer self-assembled structures. Namely, spherical, hexagonally packed cylindrical, and lamellar micro domains including fibril structure were formed, confirmed by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS), depending on the weight fraction of P3HT (w(P3HT)). Even at a w(P3HT) = 0.72, lamellar microdomains were observed because of the curvature effect resulting from miktoarm architecture at the interface between two blocks. The result implies that the macromolecular architecture is one of the important factors for adjusting self-assembled morphology of P3HT-containing block copolymers. Moreover, the melting temperature of P3HT in PMMA(2)P3HT having lamellar or cylindrical morphology does not decrease compared with neat P3HT homopolymer, which means that the rod/rod interaction of P3HT was well-maintained under miktoarm architecture.</P>
Ahn, Seonghyeon,Kwak, Jongheon,Choi, Chungryong,Seo, Yeseong,Kim, Jin Kon,Lee, Byeongdu American Chemical Society 2017 Macromolecules Vol.50 No.22
<P>We investigated, via small-angle X-ray scattering and transmission electron microscopy, the morphologies of binary blend of polyisoprene-b-polystyrene-b-poly(2-vinylpyridine) (ISP) triblock terpolymer and polyisoprene-b-polystyrene (IS) diblock copolymer. An asymmetric ISP with volume fractions (f) of 0.12, 0.75, and 0.13 for PI, PS, and P2VP blocks, respectively, showed a new morphology: coexistence of spheres and cylinders with tetragonal packing. Asymmetric IS with f(I) = 0.11 and f(s) = 0.89 showed conventional body-centered cubic spherical microdomains. Very interestingly, a binary blend of ISP and IS with overall volume fractions of f(I) = 0.12, f(s) = 0.79, and f(P) = 0.09 exhibited core shell double gyroid (CSG: Q(230) space group), where PI consists of thin core and PS forms thick shell, while P2VP becomes thin matrix. It is very unusual to form CSG even at highly asymmetric volume fractions.</P>
Mishra, Avnish Kumar,Choi, Chungryong,Maiti, Sandip,Seo, Yeseong,Lee, Kyu Seong,Kim, Eunseol,Kim, Jin Kon Butterworth Scientific Ltd. etc. 2018 Polymer Vol. No.
<P><B>Abstract</B></P> <P>The sequential synthesis of well-defined poly(vinyl acetate)-<I>block</I>-polystyrene copolymer (PVAc-<I>b</I>-PS) and poly(vinyl alcohol)-<I>block</I>-polystyrene copolymer (PVA-<I>b</I>-PS) is challenging due to inactive vinyl acetate monomer and active styrene monomer. In this study, sequential polymerizations of vinyl acetate and styrene monomer were carried out by reversible addition-fragmentation chain transfer (RAFT) and atom transfer radical polymerization (ATRP) using an innovative amide based difunctional chloroamide-xanthate iniferter [S-(1-((3-(2-chloropropanamido)propyl) amino)-1-oxopropan-2-yl) <I>O</I>-ethyl xanthate]. Synthesized difunctional iniferter was very stable under basic condition and allowed the sequential reactions without chain-end modification and purification steps. Synthesized iniferter was first used for xanthate-mediated RAFT polymerization of VAc, followed by ATRP of styrene to achieve controlled molecular weight of PVAc-<I>b</I>-PS with lower polydispersity (≤1.3). Then, PVAc-<I>b</I>-PS was successfully converted to the corresponding PVA-<I>b</I>-PS by hydrolysis. Synthesized block copolymers were characterized by size exclusion chromatography, nuclear magnetic resonance spectroscopy, transmission electron microscopy, and dynamic light scattering.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of amide based difunctional chloroamide-xanthate iniferter. </LI> <LI> Sequential synthesis of well-defined poly(vinyl acetate)-<I>block</I>-polystyrene block copolymer with lower polydispersity (≤1.3). </LI> <LI> Successful synthesis amphiphilic poly(vinyl alcohol)-<I>block</I>-polystyrene block copolymer through hydrolysis. </LI> <LI> Investigate the micelle formation of PVAc-<I>b</I>-PS and PVA-<I>b</I>-PS in a selective solvent. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Self-Positioned Nanosized Mask for Transparent and Flexible Ferroelectric Polymer Nanodiodes Array
Hyun, Seung,Kwon, Owoong,Choi, Chungryong,Vincent Joseph, Kanniyambatti L.,Kim, Yunseok,Kim, Jin Kon American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.40
<P>High density arrays of ferroelectric polymer nanodiodes have gained strong attention for next-generation transparent and flexible nonvolatile resistive memory. Here, we introduce a facile and innovative method to fabricate ferroelectric polymer nanodiode array on an ITO-coated poly (ethylene terephthalate) (PET) substrate by using block copolymer self assembly and oxygen plasma etching. First, polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) micelles were spin-coated on poly(vinylidene fluoride-ran-trifluoroethylene) copolymer (P(VDF-TrFE)) film/ITO-coated PET substrate. After the sample was immersed in a gold precursor (HAuCl4) containing solution, which strongly coordinates with nitrogen group in P2VP, oxygen plasma etching was performed. During the plasma etching, coordinated gold precursors became gold nanoparticles (GNPs), which successfully acted as self-positioned etching mask to fabricate a high density array of P(VDF-TrFE)) nanoislands with GNP at the top. Each nanoisland shows clearly individual diode property, as confirmed by current-voltage (I-V) curve. Furthermore, due to the transparent and flexible nature of P(VDF-TrFE)) nanoisland as well as the substrate, the P(VDF-TrFE) nanodiode array was highly tranparent, and the diode property was maintained even after a large number of bendings (for instance, 1000 times). The array could be used as the next-generation tranparent and flexible nonvolatile memory device.</P>
Lee, Jaeyong,Kwak, Jongheon,Choi, Chungryong,Han, Sung Hyun,Kim, Jin Kon American Chemical Society 2017 Macromolecules Vol.50 No.23
<P>We studied the phase behavior of the poly(2-vinylpyridine)-block-poly(4-vinylpyridine) copolymer (P24VP) containing gold nanoparticles, by rheometry, small-angle X-ray scattering, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). Although both blocks of P24VP exhibited attractive interaction to gold precursors, unusual phase behavior was observed depending on the amount of gold nanoparticles. As the amount of gold nanoparticles increased, the order-to-disorder transition temperature (T-ODT) of P24VP with gold nanoparticles decreased first, then increased, and finally decreased again. To explain this phenomenon, We prepared two block copolymers: polystyrene-block-poly(2-vinylpyridine) copolymer (PS2VP) and polystyrene-block-poly(4-vinylpyridine) copolymer (PS4VP) containing gold nanoparticles. With increasing the amount of gold particles, the T-oDT of PS2VP increased continuously, whereas that of PS4VP gradually decreased. For PS4VP containing gold nanoparticles, because P4VP chains can interact with the gold nanoparticle surface, density fluctuations exist near the gold nanoparticle surfaces, which causes the T-oDT to decrease. On the other hand, although the pyridine ring in P2VP could be associated with the gold surface, P2VP chains become stretched due to steric hindrance arising from the ortho position of nitrogen in P2VP. The chain stretching increases the T-ODT. Thus, the decrease of T-oDT for P24VP originates from P4VP microdomains containing gold nanoparticles, while the increase of T-ODT is attributed to the P2VP microdomains containing, gold nanoparticles. With increasing the amounts of gold nanoparticles, the contribution of P4VP microdomains containing gold nanoparticles on the T-ODT becomes dominant, causing the T-oDT to redecrease. To verify the gold nanoparticle position in both P2VP and P4VP microdomains, we performed TEM and scanning transmission electron microscopy (STEM) experiments. At lower amounts of gold nanoparticles, they are mainly located inside P4VP microdomains. With increasing the amount of the gold nanoparticles, they are distributed in both P2VP and P4VP microdomains, though the amount of gold nanoparticles in P4VP microdomains is larger than that in P2VP microdomains.</P>