Ordered quasi-two-dimensional structure of nanoparticles in semiflexible ring polymer brushes under compression

Abstract

Molecular dynamics simulations of a coarse-grained bead-spring model of ring polymer brushes under compression are presented. Flexible polymer brushes are always disordered during compression, whereas semiflexible polymer brushes tend to be ordered under sufficiently strong compression. Further, the polymer monomer density of the semiflexible polymer brush is very high near the brush surface, inducing a peak value of the free energy near the surface. Therefore, when nanoparticles are compressed in semiflexible ring polymer brushes, they tend to exhibit a closely packed single-layer structure between the brush surface and the impenetrable wall, and a quasi-two-dimensional ordered structure near the brush surface is formed under strong compression. These findings provide a new approach to designing responsive applications.

Keywords

molecular dynamics simulation / semiflexible ring polymer brushes / nanoparticle / compression / ordered structure

References

[1] M. V. Reddy, T. Yu, C. H. Sow, Z. X. Shen, C. T. Lim, G. V. S. Rao, and B. V. R. Chowdari, α-Fe₂O₃ nanoflakes as an anode material for Li-ion batteries, Adv. Funct. Mater. 17(7), 2792 (2006)

[2] T. Yu, Y. W. Zhu, X. J. Xu, Z. X. Shen, P. Chen, C.T. Lim, J. T. L. Thong, and C. H. Sow, Controlled growth and field-emission properties of cobalt oxide nanowalls, Adv. Mater. 17(13), 1595 (2005)

[3] X. D. Gao, X. M. Li, W. D. Yu, F. Peng, and C. Y. Zhang, Oversized hexagonal nanosheets of layered zinc hydroxysulfates via the hexamethylenetetraminemediated solution route, Mater. Res. Bull. 41(3), 608 (2006)

[4] X. Huang, S. Tang, X. Mu, Y. Dai, G. Chen, Z. Zhou, F. Ruan, Z. Yang, and N. Zheng, Freestanding palladium nanosheets with plasmonic and catalytic properties, Nat. Nanotechnol. 6(1), 28 (2011)

[5] H. L. Wang, H. S. Casalongue, Y. Y. Liang, and H. J. Dai, NiOH₂ nanoplates grown on graphene as advanced electrochemical pseudocapacitormaterials, J. Am. Chem. Soc. 132(21), 7472 (2010)

[6] S. H. Chen and D. L. Carroll, Silver nanoplates: Size control in two dimensions and formation mechanisms, J. Phys. Chem. B 108(18), 5500 (2004)

[7] X. P. Sun, S. J. Dong, and E. Wang, Large-scale synthesis of micrometer- scale single-crystalline Au plates of nanometer thickness by a wet-chemical route, Angew. Chem. Int. Ed. 43(46), 6360 (2004)

[8] A. K. Geim, Graphene: Status and prospects, Science 324(5934), 1530 (2009)

[9] M. Q. Yang, N. Zhang, M. Pagliaro, and Y. J. Xu, Artificial photosynthesis over graphene-semiconductor composites: Are we getting better? Chem. Soc. Rev. 43(24), 8240 (2014)

[10] S. Z. Butler, S. M. Hollen, L. Cao, Y. Cui, J. A. Gupta, , Challenges and opportunities in two-dimensional materials beyond graphene, ACS Nano 7(4), 2898 (2013)

[11] J. Yu, Y. Yu, P. Zhou, W. Xiao, and B. Cheng, Morphology dependent photocatalytic H₂-production Activity of CdS, Appl. Catal. B 184(2), 156 (2014)

[12] F. Dong, L. Wu, Y. Sun, M. Fu, Z. Wu, and S. C. Lee, Efficient synthesis of polymeric g-C₃N₄ layered materials as novel efficient visible light driven photocatalysts, J. Mater. Chem. 21(39), 15171 (2011)

[13] J. Hong, Y. Wang, Y. Wang, W. Zhang, and R. Xu, Noble-metal-free NiS/C₃N₄ for efficient photocatalytic hydrogen evolution from water, ChemSusChem 6(12), 2263 (2013)

[14] X. Song, J. Hu, and H. Zeng, Two-dimensional semiconductors: Recent progress and future perspectives, J. Mater. Chem. 1, 2952 (2013)

[15] S. Khanchandani, S. Kundu, A. Patra, and A. K. Ganguli, Shell thickness dependent photocatalytic properties of ZnO/CdS core-shell nanorods, J. Phys. Chem. C 116(44), 23653 (2012)

[16] Y. Xu, W. Zhao, R. Xu, Y. Shi, and B. Zhang, Synthesis of ultrathin CdS nanosheets as efficient visiblelight- driven water splitting photocatalysts for hydrogen evolution, Chem. Commun. 49(84), 9803 (2013)

[17] Y. Yu, P. Zhang, L. Guo, Z. Chen, Q. Wu, Y. Ding, W. Zheng, and Y. Cao, The design of TiO₂ nanostructures (nanoparticle, nanotube, and nanosheet) and their photocatalytic activity, J. Phys. Chem. C 118(24), 12727 (2014)

[18] I. Y. Kim, Y. K. Jo, J. M. Lee, L. Wang, and S. J. Hwang, Unique advantages of exfoliated 2D nanosheets for tailoring the functionalities of nanocomposites, J. Phys. Chem. Lett. 5(23), 4149 (2014)

[19] T. Sagawa, S. Yoshikawa, and H. Imahori, Onedimensional nanostructured semiconducting materials for organic photovoltaics, J. Phys. Chem. Lett. 1(7), 1020 (2010)

[20] L. Yuan, M. Q. Yang, and Y. J. Xu, Tuning the surface charge of graphene for self-Assembly synthesis of a SnNb₂O₆ nanosheet-graphene (2D-2D) nanocomposite with enhanced visible light photoactivity, Nanoscale 6(12), 6335 (2014)

[21] S. Milner, Polymer brushes, Science 251(4996), 905 (1991)

[22] A. Halperin, M. Tirrell, and T. P. Lodge, Tethered chains in polymer microstructures, Adv. Polym. Sci. 100, 31 (1992)

[23] G. S. Grest, Normal and shear forces between polymer brushes, Adv. Polym. Sci. 138, 149 (1999)

[24] R. C. Advincula, W. J. Brittain, K. C. Caster, and J. Rühe, Polymer Brushes, Weinheim: Wiley VCH, pp 427–440 (2004)

[25] G. S. Grest and K. Kremer, Molecular dynamics simulation for polymers in the presence of a heat bath, Phys. Rev. A 33(5), 3628 (1986)

[26] A. Brasiello, S. Crescitelli, and G. Milano, Development of a coarse-grained model for simulations of tridecanoin liquid-solid phase transitions, Phys. Chem. Chem. Phys. 13(37), 16618 (2011)

[27] T. Carlsson, N. Kamerlin, G. A. Arteca, and C. Elvingson, Brownian dynamics of a compressed polymer brush model: Off-equilibrium response as a function of surface coverage and compression rate, Phys. Chem. Chem. Phys. 13(35), 16084 (2011)

[28] I. G. Elliott, T. L. Kuhl, and R. Faller, Molecular simulation study of the structure of high density polymer brushes in good solvent, Macromolecules 43(21), 9131 (2010)

[29] S. Plimpton, Fast parallel algorithms for short-range molecular dynamics, J. Comput. Phys. 117(1), 1 (1995)

[30] W. Humphrey, A. Dalke, and K. Schulten, VMD – Visual molecular dynamics, J. Mol. Graph. 14(1), 33 (1996)

[31] Y. F. Hua, L. X. Zhang, and L. Zhang, Compressiondriven migration of nanoparticles in semiflexible polymer brushes, Polymer 83(9), 67 (2016)

[32] A. Milchev and K. Binder, Unconventional ordering behavior of semi-flexible polymers in dense brushes under compression, Soft Matter 10(21), 3783 (2014)

[33] G. M. Torrie and J. P. Valleau, Nonphysical sampling distributions in Monte Carlo free-energy estimation: Umbrella sampling, J. Comput. Phys. 23(2), 187 (1977)

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag Berlin Heidelberg