高等学校化学学报 ›› 2014, Vol. 35 ›› Issue (8): 1816-1821.doi: 10.7503/cjcu20140253

• 高分子化学 • 上一篇    下一篇

氧等离子体改性聚乙烯表面的疏水性过回复机制

李昱鹏, 张志超, 李声耀, 石伟, 雷明凯()   

  1. 大连理工大学材料科学与工程学院表面工程研究室, 大连 116024
  • 收稿日期:2014-03-24 出版日期:2014-08-10 发布日期:2014-06-30
  • 作者简介:联系人简介: 雷明凯, 男, 博士, 教授, 博士生导师, 主要从事高分子材料表面工程研究. E-mail: surfeng@dlut.edu.cn
  • 基金资助:
    国家自然科学基金(批准号: 51005032, 51321004)资助

Mechanism of Hydrophobic Over-recovery on Polyethylene Surface Modified by Oxygen Plasma

LI Yupeng, ZHANG Zhichao, LI Shengyao, SHI Wei, LEI Mingkai*()   

  1. Surface Engineering Laboratory, School of Material Science and Engineering,Dalian University of Technology, Dalian 116024, China
  • Received:2014-03-24 Online:2014-08-10 Published:2014-06-30
  • Contact: LEI Mingkai E-mail:surfeng@dlut.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(Nos.51005032, 51321004)

摘要:

用200 W射频容性耦合氧等离子体处理低密度聚乙烯(LDPE)表面1 min, 研究了老化温度及时间对LDPE表面成分、 形貌和润湿性的影响. 扫描电子显微镜结果表明, 等离子体改性LDPE表面出现纳米凸点织构, 在60和90 ℃老化24 h后纳米凸点织构特征基本保持稳定. X射线光电子能谱分析表明, 等离子体改性LDPE表面经60 ℃老化24 h后, C—C含量由76.9%增至83.0%, C—O, CO和O—CO含量分别由16.4%, 2.2%和4.5%降至13.1%, 1.9%和2.0%. 经90 ℃老化24 h后, C—C含量较60 ℃老化表面增至84.1%, C—O含量分别降至10.1%, CO和O—CO含量分别增至3.1%和2.7%. 等离子体改性LDPE表面接触角由97.2°降至42.3°, 经60 ℃老化24 h后接触角增至95.9°, 经90 ℃老化24 h后接触角增至104.2°, 等离子体改性LDPE表面发生“疏水性过回复”. 根据含有粗糙因子的接触角随时间演变模型, 得到了具有纳米凸点织构LDPE表面在不同老化温度下的可移动极性基团所占面积分数(fmp)、 固定极性基团所占面积分数(fimp)和特征时间常数(τ)3个成分重构参数, 解释了“疏水性过回复”现象.

关键词: 低密度聚乙烯, 射频容性耦合氧等离子体, 老化, 表面重构, 疏水性过回复

Abstract:

Low density polyethylene(LDPE) surface was modified by oxygen capacitively coupled plasma(CCP) under a radio frequency(RF) power of 200 W for an exposure time of 1 min. The aging process of the plasma-modified LDPE was studied at aging temperatures of 60 and 90 ℃ for an aging time of 24 h. The morphology with the nanonodules was obtained on the as-modified LDPE surface under 200 W for 1 min and was stable on the post-aged LDPE surface at 60 and 90 ℃ after 24 h. The plasma modification under 200 W for 1 min introduced lots of polar oxygen-containing groups on the as-modified LDPE surface. The aging process at 60 ℃ after 24 h aroused the decrease of the polar oxygen-containing groups on the post-aged LDPE surface and lower oxygen-containing group content appeared on the post-aged surface at 90 ℃. The as-modified hydrophi-lic surface with the contact angle of 42.3° underwent the hydrophobic recovery into hydrophobicity on the post-aged surface with the contact angle of 95.9° at 60 ℃ after 24 h similar to the original LDPE surface with 97.2°, and further hydrophobic over-recovery into higher hydrophobicity of the post-aged surface with the contact angle of 104.2° at 90 ℃ after 24 h than the original surface. Based on the time-dependent contact angle model for the aging of the rough surface containing different wetting patches, the surface restructuring on the plasma-modified LDPE surface experiencing the hydrophobic over-recovery during aging process was quantitatively analysized.

Key words: Low density polyethylene(LDPE), Oxygen capacitively coupled radio frequency plasma, Aging, Surface restructuring, Hydrophobic over-recovery

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