Theoretical Study on Enhancement of Sensing Capability of Plasmonic Dimer Au Nanoparticles with Amphiphilic Polymer Brushes

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• 作者：Eun Min Go ; Tae Kyung Lee ; Sa Hoon Min ; Woo Cheol Jeon ; Byeong-Su Kim ; Min Sun Yeom ; Sang Kyu Kwak
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：May 26, 2016
• 年：2016
• 卷：120
• 期：20
• 页码：11068-11077
• 全文大小：668K
• 年卷期：0
• ISSN：1932-7455

文摘

Au nanoparticle (Au-NP) sensors need a high surface plasmon resonance intensity and a low steric effect for efficient labeling in sensors. Since dimers meet these requirements, we have theoretically studied the self-assembly of monomer and dimer Au-NPs by considering influential factors such as Au-NP size, polymer thickness, and gap distance between dimer Au-NPs. In order to control the monomerization and dimerization of spherical Au-NPs and their sizes via self-assembly, two polymers (hydrophilic PEG and hydrophobic PMMA) were grafted on the Au-NPs as amphiphilic brushes. Computational methods of dissipative particle dynamics and discrete dipole approximation were employed for virtual self-assembly and theoretical analyses of plasmons related to sensing properties, respectively. We found that the bigger Au-NPs were obtained when the amounts of each polymer were roughly identical and the gap distance between Au-NPs in the dimer was shorter when the amount of PMMA was reduced within the condition of dimerization. This theoretical study revealed an optimal near-contact distance for Au-NPs@PMMA/PEG, where the electron tunneling effect was minimized, and reported unseen roles of polymers and plasmons, which consequently allowed achieving a highly efficient Au-NP dimer sensor.