Hollow silica particles (HSPs) are versatile materials that could find use in many applications, from drug delivery, light-scattering, thermal and sound insulation, etc. Most often, hollow particles are made through silica deposition onto a template, which is often destructively removed through calcination. Designing mechanical stability of hollow particles is important for both the applications where they need to remain intact as well as those where they need to break down. We have made a series of HSPs with increasing wall thickness through a template approach. Mercury porosimetry (MIP) was then used to determine their mechanical stability, which represents the novel use of the technique. The study showcases the ability to design the mechanical stability of hollow particles for a variety of uses.<br/><br/>One of the problems preventing wide use of HSPs lies in their cost as well as extremely dilute tetraethoxysilane (TEOS) conditions under which they are most often made. We have developed a cost-effective method for hollow silica, which rests on using sodium silicate. This atom-economical, inexpensive silica precursor allows for much higher concentration during the template-coating step (10wt% vs. &lt;1wt% for TEOS-based routes). In addition to that, we have used a methyl methacrylate (MMA)-based template that can be thermally depolymerized, thereby opening a possibility of template recycle, without the need for organic solvents.  In the present study, 78% of MMA used for template synthesis was recycled from core/shell particles, demonstrating the possibility of making hollow particles under conditions suitable for industrial scale-up without compromising the strict control of their parameters.

Hollow silica particles: Measurement of mechanical stability through mercury porosimetry, and development of a low cost, scalable process for hollow silica

253rd National Meeting (2017)

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