Fabrication and analysis of nanoscale geometric structure on polymer substrate

유성광,고흥조,황영규 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Polymer substrates have been widely used for the development of flexible electronic devices. Recent research has focused on fabricating a geometric structure on the polymer substrate to provide the adhesive ability for wearable electronic devices. However, the behavior of the geometric structure does not seem to be well studied. In this research, we fabricated a nanoscale geometric structure with diverse diameters and lengths on a polymer substrate. We carried out mechanical analysis on the adhesion using the nano-structures together with demonstration of attachable electronic devices to show utility of this method.

플라스틱기반 평판디스플레이 장치를 위한 고분자 필름 기판위에 증착된 알류미늄 박막 특성

이명재,곽성관,정관수 경희대학교 레이저공학연구소 2001 레이저공학 Vol.12 No.-

Al films (1000∼4000Å)were deposited on glass and polymer(polyethersulfone) substrates by DC-magnetron sputtering for plastic-based flat-panel displays. A stepped heating process was used both to improve the electrical characteristics and to diminish the thermal expansion of the polymer substrates. Following this procedure, we could succeed in sputtering Al films without any cracking or shrinkage of the polymer substrates. Scanning Electrom Microscopy, Atomic Force Microscopy, X-ray Dffractometry, and electrical measurements such as resistivity measurements were performed to investigate the properties of deposited the Al films and their reliability.

콘크리트 보수용 폴리머 복합재료의 접착강도 특성

신영수,연규석,이윤수,지경용 강원대학교 부설 석재복합신소재 제품연구센터 1999 석재연 논문집 Vol.4 No.-

이 연구는 기존 시멘트 콘크리트 구조물의 표면층과 보수용 폴리머 모르터의 접착강도 특성을 구명키위해 폴리머 결합재의 종류, 결합재 첨가량, 모재의 표면상태를 변수로하여 실험한 것이다. 폴리머 시멘트 모르터제조에 상용된 재료는 시멘트 혼화용 폴리머로서 styrene-butadiene rubber (SBR)를 사용하였고, 폴리머 모르터의 결합재로는 에폭시 수지 (EP)와 불포와 폴리에스터 수지 (UP)를 사용하였다. 실험결과 모재가 건조상태인 경우 습윤상태보다 강도가 높게 나타나 모재의 상태가 건조한 것이 접착강도에 유리한 것으로 나타났으며, 폴리머 시멘트 모르터가 폴리머 모르터에 비해 접착강도가 낮음을 알 수 있었다. The adhesion properties of polymer mortars for cement concrete repair were evaluated with respect to polymer types, binder ratios and the surface conditions of cement concrete substrate. Styrene-butadiene rubber (SBR) was used as an additive for polymer cement mortar and epoxy resin (EP) and unsaturated polyester resin (UP) were used as binders for polymer mortars. The adhesion strength of polymer cement mortar was smaller than that of polymer mortar. The adhesion strengths to the dry surfaces of substrate were larger than those to the wet surfaces, indicating that the dryness of substrate increased the adhesion strength in repairing concrete structures.

Surface modification of polymeric substrates to enhance the barrier properties of an Al₂O₃ layer formed by PEALD process

Kim, Hyun Gi,Lee, Jong Geol,Kim, Sung Soo ELSEVIER 2017 Organic Electronics Vol. No.

<P><B>Abstract</B></P> <P>Aluminum oxide (Al<SUB>2</SUB>O<SUB>3</SUB>) layers were deposited on various polymeric substrates by a low frequency plasma-enhanced atomic layer deposition (PEALD) process. Polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polyethersulfone (PES) were tested as substrates for barrier films. Each substrate has its own characteristics to have influences on the Al<SUB>2</SUB>O<SUB>3</SUB> layer formation and penetration into the substrate, which greatly affected the barrier properties. Prior to the deposition process, polymeric substrates were pretreated in argon and oxygen plasmas, and surface energy was leveled up due to the formation of polar group. Characterizations of the Al<SUB>2</SUB>O<SUB>3</SUB> layer by Time of Flight - Secondary Ion Mass Spectrometry (ToF-SIMS) revealed that plasma treatment lowered the level of OH<SUP>−</SUP> in Al<SUB>2</SUB>O<SUB>3</SUB> layer. X-ray photoelectron microscopy (XPS) confirmed that A12p peak of Al<SUB>2</SUB>O<SUB>3</SUB> layer was shifted to a higher core level by plasma treatment. Density of the layer on the plasma treated surface was greater than that of untreated surface. It was found that plasma treatment of the surface had significant effects on the formation of the Al<SUB>2</SUB>O<SUB>3</SUB> layer, which much improved the barrier performance. Optical transmittance was little affected by plasma treatment and PEALD process. After oxygen plasma pretreatment, the WVTR of the Al<SUB>2</SUB>O<SUB>3</SUB> layer deposited on the plasma-treated PEN substrate was around 7.2 × 10<SUP>−4</SUP> g/m<SUP>2</SUP>day, which is significantly lower than that of the untreated substrate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Al<SUB>2</SUB>O<SUB>3</SUB> layers were formed on several polymer substrates by PEALD process, and characterizations of substrate properties were correlated with their barrier properties. </LI> <LI> The plasma pretreatment of polymer substrates with argon and oxygen prior to PEALD process much enhanced the barrier properties. </LI> <LI> The Al<SUB>2</SUB>O<SUB>3</SUB> layer formed on plasma-treated polymer substrates have a low level of OH<SUP>−</SUP> impurities and a higher refractive index compared to untreated samples. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Enhancement of the barrier property was attributed to the formation of a dense and conformal Al<SUB>2</SUB>O<SUB>3</SUB> layer by surface modification of the various polymer substrates.</P> <P>[DISPLAY OMISSION]</P>

Surface Metallization and Ceramic Deposition on Thermoplastic‑Polymer and Thermosetting‑Polymer Composite Via Atmospheric Plasma Spraying

Hansol Kwon,Jaeick Kim,Changhee Lee 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

A spray coating technique is an excellent method for surface metallization and ceramic deposition to widen the applicationfields of irreplaceable engineering polymers. In this study, Al metallization and Al2O3deposition on thermoplastic-polymers(polycarbonate, polyimide) and a thermosetting-polymer composite (carbon fiber reinforced epoxy) were conducted viaatmospheric plasma spray (APS). Due to the susceptibility of polymers to thermal or mechanical damage, precise processcontrol is required. It was shown that the engineering temperature range critically determines the process windowof thermoplastic-polymers. An Al2O3coating can be fabricated on polymers via an Al bond coat. Like a heat sink, the Albuffer layer enables polymers to endure process heating. In low thermally resistant polycarbonate (PC), only a low plasmaenergy source could be applied. Additionally, vaporization induced by Al droplet contact was a clear reason of the unstableweak interface between the coating and substrate. The coatings fabricated on polyimide (PI) substrates generally showeda continuous and clean interface with a moderate adhesion property. In the case of carbon fiber reinforced epoxy (CFRP),it is believed that carbon fibers acted as a heat sink such that considerable thermal damage of CFRP was not observed andthere was not delamination of the coatings. However, fracturing of carbon fibers and epoxy resin by grit-blasting (surfacepre-treatment) made the surface unstable. This led to the worst adhesion characteristics between the coating and CFRP substrate. It was demonstrated that because the available temperature range and surface condition are very sensitive comparedto conventional metal substrates, advanced surface pre-treatment, precise process optimization, and additional cooling arerequired for successful deposition.

나노임프린팅 기술을 이용한 유연성 브래그 반사 광도파로 소자

김경조,이정아,오민철,Kim, Kyung-Jo,Yi, Jeong-Ah,Oh, Min-Cheol 한국광학회 2007 한국광학회지 Vol.18 No.2

저가의 소자 개발이 가능한 나노임프린팅 공정을 도입하여 510 nm 주기의 브래그 격자 구조를 가지는 폴리머 광도파로 소자를 제작하였다. 폴리머 격자 광소자의 온도 의존성을 감소시키기 위한 방법으로 플라스틱 박막으로 이루어진 유연성 기판상에 브래그 격자를 제작하는 것이 필요하다. 임프린팅 공정을 손쉽게 수행하기 위한 광도파로 구조를 채택하였으며, 코아와 클래딩의 굴절률이 각각 1.540, 1.430인 폴리머를 이용하여 코아 두께가 $3{\mu}m$인 단일모드 광도파로 구조를 얻을 수 있었다. 유연성 기판 브래그 격자 광도파로 소자의 특성을 Si기판 브래그 격자 광도파로 소자와 비교하여 관측한 결과, 유연성 기판 도입에 따른 브래그 반사 소자의 성능 저하는 나타나지 않았다. Bragg reflecting waveguide devices have been fabricated on a flexible polymer substrate utilizing a post lift-off process which could Provide excellent uniformity of grating Patterns on Plastic film. The 510 m Period Bragg grating pattern is made by two methods. In the first sample the grating is fabricated by exposing the laser interference pattern on a photoresist, and then it is inscribed by $O_2$ plasma etching. The grating pattern of the second sample is formed by a PDMS soft mold imprinting process. The selective adhesion property of SU-8 material for Au and Si surfaces is utilized to prepare a 100-mm thick plastic substrate. Single mode waveguide is fabricated on the plastic substrate using polymer materials with refractive indices of 1.540 and 1.430 for the core and the cladding layers, respectively. The Bragg grating on Plastic substrate does not show any degradation in its spectral response compared to the reference sample made on a silicon wafer.

<i>In situ</i> surface selective functionalization of honeycomb patterned porous poly(ε-caprolactone) films using reactive substrate

Uyen Thi, Phan Ngoc,Male, Umashankar,Huh, Do Sung Elsevier 2018 Polymer Vol.147 No.-

<P><B>Abstract</B></P> <P>Poly (ε-caprolactone) honeycomb patterned porous films were selectively functionalized on the bottom surface with polypyrrole/silver (PPy/Ag) composite via <I>in situ</I> interfacial polymerization on a reactive substrate during the breath figure procedure. For the interfacial <I>in situ</I> polymerization, poly (ε-caprolactone) solution including pyrrole was cast on a reactive ice substrate. The reactive ice substrate contains aqueous methanesulfonic acid and silver nitrate as an oxidizing agent for the pyrrole monomer. FT-IR, EDX, UV-Visible, conductivity, and wetting measurements support the formation of PPy/Ag on the bottom surface of the films. Pore size, conductivity, and wettability increased with increased concentration of pyrrole. Films with different functionalization on either surfaces can be applied in various advanced applications such as flexible electrodes, tissue engineering, etc.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bottom functionalized patterned films were fabricated using reactive substrate. </LI> <LI> Breath figure process was performed on top surface. </LI> <LI> Interfacial polymerization was performed on bottom surface. </LI> <LI> Color, composition, wetting, conductivity are different on top and bottom surfaces. </LI> <LI> Films might have a great promising potential in advanced applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Nanoparticle-Functionalized Polymer Platform for Controlling Metastatic Cancer Cell Adhesion, Shape, and Motility

Lee, Hyojin,Jang, Yeongseon,Seo, Jinhwa,Nam, Jwa-Min,Char, Kookheon American Chemical Society 2011 ACS NANO Vol.5 No.7

<P>Controlling and understanding the changes in metastatic cancer cell adhesion, shape, and motility are of paramount importance in cancer research, diagnosis, and treatment. Here, we used gold nanoparticles (AuNPs) as nanotopological structures and protein nanocluster forming substrates. Cell adhesion controlling proteins [in this case, fibronection (Fn) and ephrinB3] were modified to AuNPs, and these particles were then modified to the layer-by-layer (LbL) polymer surface that offers a handle for tuning surface charge and mechanical property of a cell-interfacing substrate. We found that metastatic cancer cell adhesion is affected by nanoparticle density on a surface, and ∼140 particles per 400 μm<SUP>2</SUP> (∼1.7 μm spacing between AuNPs) is optimal for effective metastatic cell adhesion. It was also shown that the AuNP surface density and protein nanoclustering on a spherical AuNP are controlling factors for the efficient interfacing and signaling of metastatic cancer cells. Importantly, the existence of nanotopological features (AuNPs in this case) is much more critical in inducing more dramatic changes in metastatic cell adhesion, protrusion, polarity, and motility than the presence of a cell adhesion protein, Fn, on the surface. Moreover, cell focal adhesion and motility-related paxillin clusters were heavily formed in cell lamellipodia and filopodia and high expression of phospho-paxillins were observed when the cells were cultured on either an AuNP or Fn-modified AuNP polymer surface. The ephrin signaling that results in the decreased expression of paxillin was found to be more effective when ephrins were modified to the AuNP surface than when ephrinB3 was directly attached to the polymer film. The overall trend for cell motility change is such that a nanoparticle-modified LbL surface induces higher cell motility and the AuNP modification to the LbL surface results in more pronounced change in cell motility than Fn or ephrin modification to the LbL surface.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-7/nn202103z/production/images/medium/nn-2011-02103z_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn202103z'>ACS Electronic Supporting Info</A></P>

Effect of Sintering Time at Low Temperature on the Properties of IGZO TFTs Fabricated by Using the Sol-gel Process

최준혁,심종현,황수민,박경,김형섭,이후정,문미란,정동근,임준형,주진호 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.61

We explored the application of the sol-gel process technique to the fabrication of InGaZnO (IGZO) thin film transistors (TFTs). We fabricated IGZO TFTs by using the sol-gel method and evaluated the effect of the sintering time on the electrical properties of the IGZO system with an atomic ratio of In:Ga:Zn = 2:1:1. In the process, IGZO precursor solutions were prepared by mixing In nitrate, Ga nitrate, and Zn acetate and were then deposited on a p-type Si-wafer covered with a thermallygrown SiO2 layer by spin-coating. The sintering process was performed for 3 h, 6 h or 12 h at 300 ℃ in the ambient atmosphere. The source/drain electrodes of the TFT devices were fabricated using Al thermal evaporation. For all of the samples, a low off current (∼10−11 A) and on-to-off current ratio (∼5 × 10 4) were obtained in their transfer curves. The saturation mobility increased with increasing sintering time: for the samples sintered for 3 h, 6 h and 12 h, the saturation mobilities were calculated to be 0.825 cm2/Vs, 1.65 cm2/Vs, and 2.06 cm2/Vs, respectively. Based on the XPS and TEM analyses, the enhancement of the mobility was attributed to the increase in the number of oxygen vacancies and the nanocrystalline structure in the amorphous matrix with increasing sintering time. These results demonstrate for the potential application of sol-gel processed IGZO devices on flexible polymer substrates.

Facile and effective antibacterial coatings on various oxide substrates

김대욱,문정미,박소영,최준식,조우경 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.68 No.-

This work reports a facile and effective antibacterial coating for oxide substrates. As a coating material, a random copolymer, abbreviated as poly(TMSMA-r-PEGMA), was synthesized by radical polymerization of 3-(trimethoxysilyl)propyl methacrylate (TMSMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA). Polymeric self-assembled monolayers of poly(TMSMA-r-PEGMA) were formed on various inorganic oxide substrates, including silicon oxide, titanium dioxide, aluminum oxide, and glass, via the simple dip-coating process. The polymer-coated substrates were characterized by ellipsometry, contact angle measurements, and X-ray photoelectron spectroscopy. The bacterial adhesion on the polymer-coated substrates was completely suppressed compared to that on the uncoated substrates.