采用数值模拟方法对气体分子在两类新型氟取代聚对二甲苯聚合物(Parylene AF4、Parylene AF8)中的溶解、扩散和渗透行为进行了研究。基于COMPASS力场,利用 Material Studio (MS)软件,构建了含300个F代对二甲苯单元的长链模型,经过能量最小化和“退火”处理,获得了较为合理的模型。在此基础上,计算了两种聚合物的自由体积,结果表明, Parylene AF4、Parylene AF8具有较小的自由体积,不易形成分子渗透的有效通道。结合分子动力学(MD )和巨正则蒙特卡洛方法(GCMC),计算获得了几种气体分子在 Parylene AF4、Parylene AF8中的扩散系数、溶解系数和渗透系数。结果显示,与前期 C 型Parylene聚合物的研究数据相比,F 取代 Parylene 聚合物对较大的渗透剂分子有更好的阻隔性。分子动力学模型说明气体分子在Parylene C聚合物中的扩散符合跳跃机理。
In this paper,numerical simulations were performed to study the solubility,diffusion,permeability of gas molecules in fluorine substituent polymers (Parylene AF4 and Parylene AF8).A model of the molecular chain for Parylene AF4 and Parylene AF8 polymer with 300 repeat units was established and structural opti-mized with energy minimization and annealing based on the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS)force field in material studio (MS)software of accelrys.The free vol-ume and its distributions in the polymeric model indicated that the Parylene AF4 and Parylene AF8 had small free volume,it was not easy to form the available channel for gas molecules permeation.The diffusion,solubil-ity and permeability coefficients of some gaseous molecules in the model were also calculated based on the com-bined methods of molecular dynamics (MD)with great canonical Monte carlo methods (GCMC).In contrast with the results of previous research on Parylene C,the simulated data showed that Parylene AF4 and Parylene AF8 have better barrier for the larger size molecules (such as H2 O,H2 S,SO2 ,Cl2 ,et al).The trajectories of penetrant molecules diffusing in the model demonstrated that the molecules transferred or moved in polymer with a “hopping diffusion”behavior.
参考文献
| [1] | 李永升,帅茂兵,周元林,陈慧,唐贤臣,董发勤,肖斌.聚氯代对二甲苯薄膜表面用紫外光固化漆的制备与表征[J].功能材料,2013(08):1094-1097. |
| [2] | Eissa M .Semiconductor device having perfluorinated and non-fluorinated parylene intermetal dielectric[P].US Patent:5828132,1998-10-27. |
| [3] | Sutcliffe R.;Gaynor JF.;Luttmer JD.;Martini D.;Kelber J. Plano MA.;Lee WW. .Characterization and aluminum metallization of a parylene AF-4 surface[J].Applied Surface Science: A Journal Devoted to the Properties of Interfaces in Relation to the Synthesis and Behaviour of Materials,1998(1/2):43-56. |
| [4] | William R. Dolbier Jr;William F. Beach .Parylene-AF4: a polymer with exceptional dielectric and thermal properties[J].Journal of Fluorine Chemistry,2003(1):97-104. |
| [5] | 赵宗峰,鲜晓斌,唐贤臣,帅茂兵,吉祥波.新型涂敷材料Parylene AF4的研究进展[J].现代化工,2008(06):23-27. |
| [6] | Lu, C.;Ni, S.;Chen, W.;Liao, J.;Zhang, C. .A molecular modeling study on small molecule gas transportation in poly (chloro-p-xylylene)[J].Computational Materials Science,2010(Suppl.1):S65-S69. |
| [7] | Bian Liang,Shu Yuan-Jie,Wang Xin-Feng.Sorption and permeation of gaseous molecules in amorphous and crystalline PPX C membranes: molecular dynamics and grand canonical Monte Carlo simulation studies[J].中国物理B（英文版）,2012(07):325-336. |
| [8] | H. Sun;P. Ren;J. R. Fried .The COMPASS force field: parameterization and validation for phosphazenes[J].Computational & theoretical polymer science,1998(1/2):229-246. |
| [9] | 魏庆华,汪焰恩,杨明明,魏生民.HA/PLA复合材料界面相互作用及其力学性能的MD模拟[J].功能材料,2013(21):3089-3093,3098. |
| [10] | Siepmann J I;Frenkel D .Configurational bias monte carlo:a new sampling scheme for flexible chains[J].Molecular Physics,1992,75(01):59-70. |
| [11] | Connolly M L .Solvent-accessible surfaces of proteins and nucleic acids[J].SCIENCE,1983,221(4612):709-713. |
| [12] | Takeuchi H;Roe R J;Mark J E .Molecular dynamics simulation of diffusion of small molecules in polymers.Ⅱ.Effect of free volume distribution[J].The Journal of Chemical Physics,1990,93(12):9042-9048. |
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