Resistance to collapse: Spherical vs. non-spherical particles. ​球形が崩壊しにくい?微粒子(数百nm領域)では世界初の検証。

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市販の水中超音波処理装置により、噴霧乾燥法で生成されたサブミクロン(直径が数百nmから1μm未満)サイズの凝集粒子の耐「脱凝集」性を世界で初めて検討した。噴霧乾燥時の加熱プロファイルを変化させることにより,直径が10nmまたは100nmの水不溶性のナノ粒子からなる、異なる形状のサブミクロン凝集体を対象にした。球状の凝集体は超音波の力に強く,くぼみやドーナツ状の凝集体は壊れやすいことがわかった。凝集体の形状が超音波操作のエネルギーバランスに重要な役割を果たすことを示している。超音波容器内のキャビテーション気泡の崩壊から生じるエネルギーは、凝集体の運動と脱凝集を促進するために利用される可能性がある。Download: Full article (著者の最終原稿) The resistance to deagglomeration of spray-dried agglomerated particles of submicron size was investigated using an ultrasonication system in water. Submicron agglomerates consisting of water-insoluble primary particles with size of 10 or 100 nm were prepared in different shapes by varying the heating profile during spray drying. Spherical agglomerates were found to be more resistant to ultrasonic forces, while dent- or doughnut-shaped agglomerates tended to break down. The results show that the shape of the agglomerate plays an important role in the energy balance of the ultrasound operation. The energy produced from the collapse of cavitation bubbles in the ultrasound vessel may be used to promote motion of the agglomerates and deagglomeration.

第1著者が在学生で、インドネシアのパジャジャラン大学(UnPad)物理学科教員になった卒業生、マレーシア工科大学(UTM)環境化学工学科教員になった卒業生との共同研究の成果です。The first author was a student, and this was the result of joint research with a graduate who became a faculty member of the Department of Physics at Universitas Padjadjaran (Indonesia) and a graduate who became a faculty member of the Department of Environmental Chemical Engineering at Universiti Teknologi Malaysia.

Download: Full article (authors’ final version)

Advanced Powder Technology https://doi.org/10.1016/j.apt.2022.103543

Deagglomeration of spray-dried submicron particles by low-power aqueous sonication

(This article was invited for Virtual Special Issue of APT2021: the 8th Asian Particle Technology Symposium)

Highlights

A low-power sonication device was used for investigating deagglomeration

The resistance to collapse of agglomerated submicron particles was investigated

The shape of the agglomerate plays an important role in the resistance

The relation between morphology changes and the collapse of bubble is discussed