Molecular simulation study of the early stages of formation of bioinspired mesoporous silica materials

Alessia Centi, Miguel Jorge

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The use of bioinspired templates, such as polyamines and polypeptides, could lead to significant improvements to the synthetic conditions at which mesoporous materials are traditionally produced, removing the need for strong pH as well as high temperature or pressure. In this work, we perform atomistic molecular dynamics simulations of 1,12-diaminododecane surfactants, in water and in the presence of silica monomers, to investigate the early stages of synthesis of one the first examples of bioinspired silica materials. Different surfactant concentrations and pH were considered, clarifying the influence of the charge state of the molecules on the self-assembly process. We show that the amphiphilic amines form stable lamellar structures at equilibrium in the range from intermediate to high pH values. In a later stage, when silica species are added to the system, our results reveal that, in the same range of pH, silicates strongly adsorb around these aggregates at the interface with water. This causes a considerable modification of the curvature of the layer, which suggests a tendency for the system to evolve from a lamellar phase to the formation of vesicle structures. Furthermore, we show that silica monomers are able to penetrate the layer spontaneously when defects are created due to surfactants head-to-head repulsion. These findings are in agreement with experimental observations and support the pillaring mechanism postulated for this class of materials. However, our simulations indicate that the aggregation process is driven by charge matching between surfactant heads and silica monomers rather than by hydrogen bond interactions between neutral species, as had been previously hypothesised.
LanguageEnglish
Pages7228-7240
Number of pages38
JournalLangmuir
Volume32
Issue number28
Early online date24 Jun 2016
DOIs
Publication statusPublished - 19 Jul 2016

Fingerprint

Silicon Dioxide
Surface-Active Agents
Silica
silicon dioxide
Surface active agents
surfactants
monomers
Monomers
simulation
Silicates
Mesoporous materials
Lamellar structures
Water
Polypeptides
polypeptides
Polyamines
Self assembly
water
Amines
Molecular dynamics

Keywords

  • silica
  • biosilicification
  • molecular simulation
  • amines
  • self-assembly
  • bolaamphiphile
  • MSU-V

Cite this

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Molecular simulation study of the early stages of formation of bioinspired mesoporous silica materials. / Centi, Alessia; Jorge, Miguel.

In: Langmuir, Vol. 32, No. 28, 19.07.2016, p. 7228-7240.

Research output: Contribution to journalArticle

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