APTS-SiO2 enabled field-induced rapid assembly in low-loading suspensions
Year: 2026
Type: article
Abstract: Electrically responsive colloidal suspensions typically require either high particle concentrations or intricate conductive structures to achieve strong field-induced rheological effects. Those conditions often lead to increased viscosity off-field, particle aggregation, and electrical instability. An important question arises regarding whether the electro-response of a simple dielectric particle system can be improved by modifying the particle interface alone. In this research, we functionalized SiO 2 nanoparticles with (3-aminopropyl)triethoxysilane (APTS) to create interfacial asymmetry and study its impact on field-induced assembly in low-loading suspensions. The APTS modification introduced surface amine groups, preserved the amorphous silica structure, and improved dispersion. During voltage ramping, pure SiO 2 suspensions showed a gradual shear stress increase, reaching 1.34–4.96 Pa at 3 kV/mm for 1–3 wt%, while APTS–SiO 2 achieved 8.45–25.32 Pa under identical conditions, representing up to 2,311% improvement over off-field stress. Steady shear tests confirmed this result: at 3.0 kV/mm, the dynamic yield stress for 3 wt% APTS–SiO 2 was 17.82 Pa, compared to 3.67 Pa for pure SiO 2 , with the field-sensitivity exponent rising from 0.90 to 1.77. Pulsed-field experiments demonstrated rapid, reversible switching, and microscopy revealed dense chain formation in APTS–SiO 2 within 7 s at 1 kV/mm, whereas pure SiO 2 exhibited delayed and weaker structuring. DFT calculations revealed that the APTS–SiO2 interface exhibits localized hydrogen bonding and asymmetric electrostatic potential redistribution, supporting increased interfacial polarization during field activation. These findings illustrate that interfacial asymmetry is an effective design approach to enhance field-induced assembly and rheological performance in low-loading dielectric suspensions.
Source: Applied Surface Science
Institution: Texas A&M University
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,930
OpenAlex ID: W7203616454