Article
  • Synthesis and Properties of Hyperbranched Polyester with Second-Order Optical Nonlinearity
  • Lee JH, Lee KS
  • 2차 비선형 광학 초분지형 폴리에스테르의 합성 및 특성
  • 이종협, 이광섭
Abstract
A nonlinear optical hyperbranched polyester (PE-Azo/Hyper) was synthesized from 4-[N,N-bis(hydroxyethyl)amino-4'-formyl]azobenzene and cyanoacetic acid by a Knoevenagel polycondensation using 4-(dimethylamino)pyridine as a base. The resulting polymer was soluble in polar aprotic solvents such as N,N-dimethylformamide and 1-methyl-2-pyrrolidinone and could be processed into optical quality films by spin coating. The molecular weight was determined to be Mw=61,800 (Mw/Mn=1.86) by gel permeation chromatography using polystyrene as a standard. No melting point was detected by differential scanning calorimeter, indicating that this polymer presents an amorphous state. It shows a glass transition temperature of 121 ℃. The second-order nonlinear optical coefficient d(33) of the poled polymer determined by the second harmonic generation at 1064 nm was 25.4 pm/V.

새로운 개념의 초분지형 비선형 광학 고분자 (PE-Azo/Hyper)를 AB2형의 기능기를 가지는 단량체 4-[N,N-bis(hydroxyethyl)amino-4'-formyl]azobenzene (CHO-DOH)으로부터 Knoevenagel 축중합 반응을 통하여 합성하였다. 겔크로마토그래피상에서 폴리스티렌을 기준시료로 측정된 중합체의 무게평균분자량은 Mw=61,800 (Mw/Mn=1.86)이었고, 중합체의 용해도를 조사한 결과 1-methyl-2-pyrrolidinone, N,N-dimethylformamide 등의 반양자성 극성 유기용매에 잘 녹았으며 따라서 이들 용매를 이용하여 양질의 박막성형이 가능하였다. 또한 열시차 분석법으로 중합체 PE-Azo/Hyper의 열적 성질을 조사한 결과 녹는점이 관찰되지 않아 무정형으로 판명되었으며 유리 전이 온도는 121℃로 나타났다. 폴링에 의하여 극성 배향된 중합체 박막의 2차 비선형 계수를 Nd:YAG 레이저 (1064 nm)를 이용하여 Maker fringe 방법으로 측정한 결과 d33 = 25.4 pm/V로 비교적 높은 값을 나타내어 초분지형 고분자에서도 극성배향이 이루어져 비선형성이 발현됨을 관찰할 수 있었다.

Keywords: hyperbranched polymer; poling; optical nonlinearity

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  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2022 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 2001; 25(6): 803-810

    Published online Nov 25, 2001

  • Received on Sep 18, 2001