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

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.