Inhomogeneous distribution of crosslinks in ion tracks in polystyrene and polysilanes
Inhomogeneous distribution of crosslinks in ion tracks in polystyrene and polysilanes
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DOI：
10.1103/physrevb.70.144203
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发表时间：
2004-10-01
影响因子：
3.7
通讯作者：
Tagawa, S
中科院分区：
文献类型：
--
作者：
Seki, S;Tsukuda, S;Tagawa, S
本文研究了30-200 keV Ga、Si和Au离子束辐照聚苯乙烯、聚甲基苯基硅烷和聚二正己基硅烷所引起的GdR，并与MeV级离子束的线性能量转移所引起的GdR进行了比较。使用Charlesby-Pinner关系计算了交联的表观G值（每100 eV吸收剂量的交联），并且显示出显着低于相应MeV离子束的值。这种降低归因于离子轨道半径的减小和交联点密度的增加。通过Charlesby-Pinner关系获得的表观交联G值仅代表有助于凝胶化的交联点，并且在该关系中不计算其他点，例如离子轨道核心中的分子内交联。离子径迹的总体积被认为是确定由离子束产生的凝胶分数的最重要的特征。提出了一种新的配方，提供了一个很好的解释的聚合物的凝胶化，适用于离子束的能量keV至MeV的顺序。
Gelation in polystyrene, poly(methylphenylsilane), and poly(di-n-hexylsilane) induced by irradiation with 30-200 keV Ga, Si, and Au ion beams is examined and compared with that induced by MeV-order ion beams of similar linear energy transfer. The apparent G values of crosslinking (crosslinks per 100 eV absorbed dose) are calculated using the Charlesby-Pinner relationship, and shown to be dramatically lower than for the corresponding MeV ion beams. This decrease is attributed due to the reduced ion track radius and an increase in the density of crosslinking points. The apparent crosslinking G value obtained by the Charlesby-Pinner relationship represents only the crosslinking points contributing to gelation, and other points such as intramolecular crosslinking in the core of the ion track are not counted in the relationship. The total volume of ion tracks is considered to be the most important feature determining the gel fraction produced by the ion beams. A new formulation that provides a good explanation of the gelation of the polymer is proposed, with applicability to ion beams with energy of keV to MeV order.