Preparation and Characterization of Temperature-Triggered Microcapsules Fabricated via Low-Temperature Shear Method.
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| Title: | Preparation and Characterization of Temperature-Triggered Microcapsules Fabricated via Low-Temperature Shear Method. |
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| Authors: | Xie, Zhitian1 (AUTHOR), Wang, He1 (AUTHOR), Song, Wei1 (AUTHOR), Xu, Chentao1 (AUTHOR), Liu, Shicheng1 (AUTHOR), Niu, Xiaokai1 (AUTHOR) metronxk@126.com, Qi, Meng1 (AUTHOR) |
| Source: | Materials (1996-1944). May2026, Vol. 19 Issue 9, p1799. 26p. |
| Subjects: | Microencapsulation, Thermoresponsive polymers, Fabrication (Manufacturing), Smart materials |
| Abstract: | Highlights: A novel composite core design strategy is proposed for the encapsulation of highly alkaline sodium silicate. A temperature-responsive microcapsule system is fabricated via a one-step low-temperature shear method. HPMC serves triple functions: chemical buffer, rheology modifier, and built-in temperature trigger. The microcapsules exhibit favorable short-term alkali resistance and distinct temperature-triggered release behavior. This work provides a new methodological approach for the design of stimuli-responsive microcapsules for cement-based grouting materials. Emergency leakage repair in subway shield tunnels requires a technique to encapsulate highly reactive sodium silicate that is simple and field-deployable, yet no mature solution currently exists. The challenge lies in sodium silicate's strong alkalinity and high osmotic pressure, both of which corrode most shell materials. This study proposes a "composite core" concept—functionally re-engineering the core rather than relying on complex shell chemistries. Using hydroxypropyl methylcellulose (HPMC) as the key material, temperature-triggered microcapsules with a nano-silica shell and sodium silicate–HPMC core were fabricated via low-temperature shear. Low temperature (10–15 °C) is critical: it suppresses side reactions and tunes viscosity to 2000–5000 cP, facilitating shear dispersion. The resulting microcapsules exhibit well-defined morphology with a dense shell. Temperature response tests reveal distinct release onset at ~30 °C (HPMC's LCST): HPMC chain collapse generates internal stress that ruptures the shell, driving progressive sodium silicate release. Alkaline resistance tests confirm that intact microcapsules remain stable in high-pH environments (pH ≈ 13.2) for 30 min. This work validates the "composite core" concept and provides a simple, field-operable route to fabricate temperature-triggered microcapsules for emergency repair applications. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Highlights: A novel composite core design strategy is proposed for the encapsulation of highly alkaline sodium silicate. A temperature-responsive microcapsule system is fabricated via a one-step low-temperature shear method. HPMC serves triple functions: chemical buffer, rheology modifier, and built-in temperature trigger. The microcapsules exhibit favorable short-term alkali resistance and distinct temperature-triggered release behavior. This work provides a new methodological approach for the design of stimuli-responsive microcapsules for cement-based grouting materials. Emergency leakage repair in subway shield tunnels requires a technique to encapsulate highly reactive sodium silicate that is simple and field-deployable, yet no mature solution currently exists. The challenge lies in sodium silicate's strong alkalinity and high osmotic pressure, both of which corrode most shell materials. This study proposes a "composite core" concept—functionally re-engineering the core rather than relying on complex shell chemistries. Using hydroxypropyl methylcellulose (HPMC) as the key material, temperature-triggered microcapsules with a nano-silica shell and sodium silicate–HPMC core were fabricated via low-temperature shear. Low temperature (10–15 °C) is critical: it suppresses side reactions and tunes viscosity to 2000–5000 cP, facilitating shear dispersion. The resulting microcapsules exhibit well-defined morphology with a dense shell. Temperature response tests reveal distinct release onset at ~30 °C (HPMC's LCST): HPMC chain collapse generates internal stress that ruptures the shell, driving progressive sodium silicate release. Alkaline resistance tests confirm that intact microcapsules remain stable in high-pH environments (pH ≈ 13.2) for 30 min. This work validates the "composite core" concept and provides a simple, field-operable route to fabricate temperature-triggered microcapsules for emergency repair applications. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 19961944 |
| DOI: | 10.3390/ma19091799 |
