Search

PDMS modified epoxy resin with epoxy group (EMPDMS) was prepared from the reaction of α,ω-aminopropylpolydimethylsiloxane and diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin, and PDMS modified epoxy hybrid compound (EMPDMSH) was prepared by introducing alkylesteraminopropyl alkoxy silane to EMPDMS. Their structures were characterized using FT-IR, 1 H-NMR and 29 Si-NMR. Coating materials were prepared by mixing EMPDMSH base and solvent. Physical properties of the coating materials coated on epoxy/glass fiber composite film were measured according to the content of PDMS in EMPDMSH. Contact angle of coating film was increased 30 to 71 degree. Adhesive property of coating film was 5B degree better then epoxy or acrylate coating materials, and surface roughness was decreased as increasing in EMPDMSH.

Polydimethylsiloxane(PDMS)을 이용한 실리콘 변성 에폭시(PDMSME) 언더코팅액의 변성 조건이 코팅 도막물성에 미치는 영향을 살펴보았다. 실리콘 변성 에폭시 언더코팅 도막은 에폭시 코팅 도막에 비하여 월등히 우수한휨성을 가지며 경도는 PDMS에 결합된 실란 커플링제에 의해 개환된 에폭시 링의 개수와 밀접한 관계를 가짐을 알수 있었다. PDMS에 결합된 개환된 에폭시 링의 개수가 증가함에 따라 대기 중의 수분과의 수가교에 의한 가교밀도 증가에 의하여 경도가 증가되며 사용된 PDMS의 탄성적 성질에 의하여 휨성 또한 우수해짐을 알 수 있었다. PDMS 분자량이 증가됨에 따라 코팅 도막의 경도는 낮아지는 반면 실리콘의 함량 증가에 따른 표면 접촉각이 증가됨을 알 수 있었다. 이와 함께 PDMS의 분자량이 증가됨에 따라 아세톤 용액에 의한 PDMSME 주사슬의 entanglement감소에 의하여 코팅액의 점도가 감소되며 그 결과, 언더코팅 도막의 표면 거칠기가 감소됨을 알 수 있었다.

The interfacial adhesion strength is very important in deposited PC film for the barrier enhanced polycarbonate (PC) flexible substrate. In this study, PC films were treated by undercoating, UV/ and low temperature plasma and then the effect of physical and chemical surface modifications on the interfacial adhesion strength between PC film and barrier layer were studied. It was found that untreated PC film shows significantly low interfacial adhesion strength due to the smooth surface and low surface free energy of PC. Low temperature plasma treatments resulted in the increase of both surface roughness and surface free energy due to etching and the appearance of polar molecules on the PC surface. However, UV/ treatment only shows the increase of surface free energy by developed polar molecules on the surface. These surface modifications caused the enhancement of surface interfacial strength between PC film and barrier. In the case of undercoating, it was found that the increase of surface interfacial strength was achieved by adhesion between various acrylic acid on acrylate coated surface and without increase of polar surface energy. In addition, the barrier property is also improved by organic-inorganic hybrid multilayer structure.

A numerical model based on Berreman’s 4 × 4 matrix approach was developed and used for computational simulation of a cholesteric liquid crystal (CLC) polarizer. Explicit expressions of the 4 × 4 propagation matrices for several optical films, which constitute a CLC polarizer, were presented. Numerical simulations for optical properties of a CLC layer, a linear polarizer and a CLC polarizer were executed, and the simulated results were found to be in fairly good agreement with measured results.

In this work, we developed a thin calcium degradation method introducing sensitive electrical resistance monitoring. We have demonstrated structural models of the inorganic/organic thin films to evaluate barrier properties against water and oxygen permeation. The time-dependent transmission curve of a multibarrier coated on both sides of the polyethersulfone substrate had a linear slope which was measured as 5.17 x 10(-3) gm(2) day at 20 degrees C and 60% relative humidity. This system can measure an accurate permeation rate with a high sensitivity in the measurable range of 10(1)-10(-6) gm(2) day. In addition, the test structure devised is applicable to various fabrication techniques for passivation layers with durability and ultralow permeability for flexible organic light emitting diodes.

We report on a measurement system including an analysis of an electrical mechanism based on calcium degradation. A quantitative water permeation rates were measured in the range of 101−10−5 g/m2day. Our test structure and measurements principle results in an application to evaluate the polymeric barrier performances for flexible electronics.