Jump to main content
Jump to site search

Issue 13, 2019
Previous Article Next Article

Natural rubber–SiO2 nanohybrids: interface structures and dynamics

Author affiliations

Abstract

Homogeneous dispersion of silica nanoparticles (SiO2 NPs) in natural rubber (NR) is a key challenge for engineering high-performance nanocomposites and elucidation of their structure on a molecular basis. Towards this, the present work devised a novel route for obtaining 3D self-assembled SiO2 NP–NR nanocomposites under aqueous conditions and in the presence of Mg2+, by establishing a molecular bridge that clamped the negatively charged NR and SiO2 colloidal particles with a favoured NR–SiO2 NP hetero-aggregation. The characteristic NR–SiO2 NP hetero-aggregates displayed a decreased heat capacity with increase in the SiO2 mass-fraction, implying a restricted NR chain mobility. Such changes in the interfacial layers were tapped by 29Si NMR, DFT calculations and molecular dynamics simulations towards a mechanistic understanding of the structure and dynamics of the NR/SiO2 NP hybrid. Simple models were used to illustrate basic ideas; specific electrostatic interactions such as ion–dipole and H-bonding interactions proved to be the driving forces for the organized assembly leading to the NR–SiO2 hetero-aggregate over the NR–NR or SiO2 NP–SiO2 NP homo-aggregate. Molecular dynamics simulation of the aqueous canonical ensemble of the hybrid showed the stable molecular conformation to reveal a SiO2 NP spherical core encapsulated by a hydrophobically interconnected NR polymer layer as the outer shell, as a unique structural model. Specifically, the lipid end of the NR was involved electrostatically while the lysine end (the protein part of NR) H-bonded to the core silica cluster thereby restricting random aggregation. The calculated negative free energy changes for the hetero-aggregate composites via their vibrational and rotational spectra proved the spontaneity of composite formation.

Graphical abstract: Natural rubber–SiO2 nanohybrids: interface structures and dynamics

Back to tab navigation

Supplementary files

Publication details

The article was received on 04 Feb 2019, accepted on 20 Feb 2019 and first published on 22 Feb 2019


Article type: Paper
DOI: 10.1039/C9SM00254E
Soft Matter, 2019,15, 2826-2837

  •   Request permissions

    Natural rubber–SiO2 nanohybrids: interface structures and dynamics

    Md. A. Sattar, A. S. Nair, P. J. Xavier and A. Patnaik, Soft Matter, 2019, 15, 2826
    DOI: 10.1039/C9SM00254E

Search articles by author

Spotlight

Advertisements