Vertical orientation of solvent cast nanofilled PS-b-PEO block copolymer thin films at high nanoparticle loading

POLYMER

卷:82

Article

Huq, Abul F.^1,6  Kulkarni, Manish^1,7  Modi, Arvind¹  Smilgies, Detlef-M.²  Al-Enizi, Abdullah M.³  Elzatahry, Ahmed^4,8  Raghavan, Dharmaraj⁵  Karim, Alamgir¹ 

[1] Univ Akron, Dept Polymer Engn, Akron, OH 44304 USA

[2] Cornell High Energy Synchrotron Source, Wilson Lab, 161 Synchrotron Dr, Ithaca, NY 14853 USA

[3] King Saud Univ, Fac Sci, Dept Chem, POB 2455, Riyadh 11451, Saudi Arabia

[4] Qatar Univ, Coll Arts & Sci, Mat Sci & Technol Program, POB 2713, Doha, Qatar

[5] Howard Univ, Dept Chem, Washington, DC 20059 USA

[6] Vis Ease Lens Worldwide, Ramsey, MN 55303 USA

[7] Indian Inst Technol, Ctr Nanosci, Kanpur 208016, Uttar Pradesh, India

[8] City Sci Res & Technol Applicat, Adv Technol & New Mat Res Inst, Polymer Mat Res Dept, Alexandria 21934, Egypt

关键词: Mixed solvent;    Block copolymer;    Hansen solubility parameter;    Nanoparticle dispersion;   

DOI  :  10.1016/j.polymer.2015.10.049

来源: Elsevier

【 摘 要 】

We demonstrate selective dispersion of photosensitive electron acceptor phenyl-C61-butyric acid methyl ester (PCBM) in cylinder forming polystyrene-b-poly (ethylene oxide) (PS-b-PEO) block copolymer (BCP). Neat PS-b-PEO is structurally robust to forming vertically oriented nanoscale morphology of PEO cylinders in the PS matrix directly after solvent casting. Varying amounts of PCBM nanoparticles were mixed with PS-b-PEO BCP in solvent mixtures and films were spin cast on UV/ozone treated clean silicon wafers. We studied in detail the BCP morphology orientation effect of different solvents and solvent mixtures for varying PCBM loading (phi(PCBM)) in the films, range from 0 to 50 weight percent relative to the BCP. The key accomplishments of this work include vertical orientation control even at large concentration of PCBM similar to 30% (w/w) particles relative to polymer mass and preferential segregation of PCBM in PS block via mixed solvent strategy which otherwise is difficult to realize due to segregation of PCBM on polar substrate. We explain the preferential dispersion of particles in films by demarcating limits in terms of critical Hansen solubility parameter. This value is close to the percolation threshold of PCBM, so a conducting polymer matrix can be expected, especially when it is partitioned preferentially in the matrix PS domain. We report changes in PEO cylinder diameter, cylinder center-to-center distance with PCBM incorporation into PS matrix, change of film thickness with overall PCBM incorporation and root mean square roughness of the film surface, for a range of casting solvents, solvent mixture compositions and fPCBM. Notably, the film thickness increased as the PCBM content in film was increased for same processing condition, so that domain swelling by nanoparticles was self-adjusting with film thickness increment. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

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