Mesoporous Silica Microspheres Composited with SBA-15s for Resonance Frequency Reduction in a Miniature Loudspeaker

Abstract

Microspheres composited with mesoporous SBA-15 particles and silica were investigated as fillers in miniature loudspeakers to study the factors influencing the resonance frequency offsets(RFOs). Mesoporous silica microspheres(MSMs) were prepared by self-assembling SBA-15 mesoporous silica in a microemulsion synthesis system. The formation process involved the fabrication of a stable O/W microemulsion of tetrabutyl orthosilicate(TBOS) and hexadecyltrimethylammonium bromide(C16TAB) and encapsulation of SBA-15s. The RFO increased and then decreased with increasing particle size(in the length range of 0.7–5.5 µm and in the width range of 0.2–0.45 µm), increased with increasing pore size(in the range of 7.0–9.4 nm) of SBA-15s, and increased with decreasing particle size(105–900 µm) of MSMs.