日本地球惑星科学連合2014年大会

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セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS36_1AM2] 結晶成長における界面・ナノ現象

2014年5月1日(木) 11:00 〜 12:45 314 (3F)

コンビーナ:*木村 勇気(東北大学)、三浦 均(名古屋市立大学大学院システム自然科学研究科)、塚本 勝男(東北大学大学院理学研究科地学専攻)、佐藤 久夫(三菱マテリアル株式会社エネルギー事業センター那珂エネルギー開発研究所)、座長:長嶋 剣(北海道大学低温科学研究所)、佐藤 久夫(三菱マテリアル株式会社エネルギー事業センター那珂エネルギー開発研究所)

12:30 〜 12:45

[MIS36-08] コロイド結晶成長における不純物の分配挙動

*野澤 純1胡 素梦1小泉 晴比古1藤原 航三1宇田 聡1 (1.東北大学,金属材料研究所)

キーワード:コロイド結晶, 不純物分配

Colloidal crystals are regarded as a promising tool to investigate diverse basic physical phenomena. We have applied this colloidal crystal to impurity partitioning in the melt growth. Since no research has been focused to detail partitioning behavior of colloidal crystals, the objective of the present work is to reveal a partitioning behavior during colloidal crystallization.A few amount of impurities (2 percent) were doped to the colloidal dispersion, from which colloidal crystals were grown with convective assembly method. Polystyrene particles (PS) were used for fabricating colloidal crystals, and different sizes of PS and fluorescent bearing PS (w/fluor.) were doped as impurity particles.In each particle size for two kinds of impurity, effective partition coefficient (keff) were measured at various growth rates. Obtained keff gives k0 by using BPS plot. The k0 is decreased as the difference between the size of the impurity and the 500 nm host particle increased. The k0 of each w/fluor. was larger than that of the corresponding pure PS. Moreover, the value of k0 for the 520 nm w/fluor. surpassed unity, whereas the PS is always less than unity. We have employed a Thurmond and Struthers (T&S) model (J. Phys. Chem. 57, 831 (1953)) to discuss the difference of k0 for PS and w/fluor. particles. T&S model shows k0 as; k0 = exp((∆GTr–∆H)/RT). Here, ∆GTr is free energy difference between the solid and liquid phases of an impurity at the transition temperature, T, ∆H is the excess enthalpy which is caused by incorporation of the impurity into the host material, and R is a gas constant. We have determined the phase transition volume fraction for PS and w/fluor. to evaluate the ∆GTr. It was shown that ∆GTr of w/fluor. is positive whereas PS is zero. This leads to larger ∆GTr–∆H of w/fluor. than that of PS, which corresponds to larger k0 of w/fluor., and in a small –∆H range, k0 of w/fluor. surpasses unity. We have found the difference of k0 for different kinds of impurity particles, and succeeded in applying concept of T&S model to partitioning of colloidal crystals.