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1. Structure of Polymer-Grafted Nanoparticle Melts

   https://doi.org/10.1021/acsnano.0c06134  

   Midya, Jiarul ; Rubinstein, Michael ; Kumar, Sanat K. ; Nikoubashman, Arash ( November 2020 , ACS Nano)

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2. Dynamics of nanoparticle assembly from disjointed images of nanoparticle-polymer composites

   https://doi.org/10.1103/PhysRevE.93.022501  

   Murthy, Chaitanya R. ; Gao, Bo ; Tao, Andrea R. ; Arya, Gaurav ( February 2016 , Physical Review E)
3. Influence of nanoparticle-ion and nanoparticle-polymer interactions on ion transport and viscoelastic properties of polymer electrolytes

   https://doi.org/10.1063/1.4946047  

   Mogurampelly, Santosh ; Sethuraman, Vaidyanathan ; Pryamitsyn, Victor ; Ganesan, Venkat ( April 2016 , The Journal of Chemical Physics)
4. Polymer Grafted Nanoparticle Viscosity Modifiers

   https://doi.org/10.1002/macp.201800543  

   Giovino, Marissa ; Buenning, Eileen ; Jimenez, Andrew ; Kumar, Sanat_K ; Schadler, Linda ( February 2019 , Macromolecular Chemistry and Physics)

   It is demonstrated that the addition of nanoparticles can decrease the viscosity of an entangled polymer matrix (plasticization). While there has been considerable effort in understanding the role of bare nanoparticles on viscosity, the corresponding study on grafted particles is nascent. Two nanometer radius zirconia fillers with a bimodal population of grafted PDMS is used. Two fillers are considered: one has grafted chains with a molecular weight, M_g, less than the entanglement M, M_g < M_e(ZrO₂1k 10k), and the other filler has grafted chains M > M_c(the critical M_e) (ZrO₂1k 36k). The ZrO₂1k 10k composites exhibit plasticization for large matrix molecular weight M_m. The ZrO₂1k 36k composites, in contrast, have Einstein‐like behavior. The plasticization effects are either due to: the small filler size relative to the tube diameter or an increase in chain mobility at the interface due to autophobic dewetting.

    

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5. Detecting bound polymer layers in attractive polymer–nanoparticle hybrids

   https://doi.org/10.1039/D1NR02395K  

   Emamy, Hamed ; Starr, Francis W. ; Kumar, Sanat K. ( August 2021 , Nanoscale)

   When polymer–nanoparticle (NP) attractions are sufficiently strong, a bound polymer layer with a distinct dynamic signature spontaneously forms at the NP interface. A similar phenomenon occurs near a fixed attractive substrate for thin polymer films. While our previous simulations fixed the NPs to examine the dilute limit, here, we allow the NP to move. Our goal is to investigate how NP mobility affects the signature of the bound layer. For small NPs that are relatively mobile, the bound layer is slaved to the motion of the NP, and the signature of the bound layer relaxation in the intermediate scattering function essentially disappears. The slow relaxation of the bound layer can be recovered when the scattering function is measured in the NP reference frame, but this process would be challenging to implement in experimental systems with multiple NPs. Instead, we use the counterintuitive result that the NP mass affects its mobility in the nanoscale limit, along with the more expected result that the bound layer increases the effective NP mass, to suggest that the signature of the bound polymer manifests as a change in NP diffusivity. These findings allow us to rationalize and quantitatively understand the results of recent experiments focused on measuring NP diffusivity with either physically adsorbed or chemically end-grafted chains. 

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