膠體一般被定義為1～10 μm之微細顆粒，由於尺寸的關係而不易因重力導致沈降，然而當兩顆粒相互接近時，會因彼此作用力的影響，導致碰撞行為的發生。關於膠體間作用力的探討，由科學家Derjaguin and Landau與Verwey and Overbeek分別 在同一年時間先後提出的理論最廣為大家所熟知，簡稱為DLVO理論。DLVO理論把膠體間作用力主要分為凡得瓦爾吸引力及靜電斥力。若是顆粒具有磁性時，外加磁場會使得顆粒間產生一額外的磁偶吸引力而相互聚集。
本研究係利用影像攝錄系統及處理軟體，觀察及分析磁性顆粒在磁場中運動行為，並與軌跡模式模擬之結果進行比較。結果發現，因為兩顆粒間隔距離隨著顆粒濃度升高而縮短，又兩顆粒間磁偶極吸引力的大小會隨著磁場強度升高而增強，因此，顆粒碰撞的特徵時間會隨著顆粒濃度的升高，或是磁場強度的增強而縮短。就兩顆粒運動軌跡圖來看，雖然兩顆粒中心點連線與磁場方向之夾角的改變，會造成運動軌跡的變化，但大部分都是呈現實驗分析與軌跡模式運算相似的情況。相異情況的發生是因為軌跡模式所模擬的情況並沒有考慮周圍顆粒的影響，所以造成在低磁場時，若兩顆粒中心點連線與磁場方向之初始夾角大於54.7度，實驗分析與模式運算所得之結果會出現截然不同的結果。

Colloid is generally defined as particle between 1 μm and 10 μm. When two particles approach each other, several types of interaction can come into play which may have a major effect on the collision process. The two most familiar colloidal interactions are van der Waals attractions and electrical repulsions, which form the basis of well-known DLVO theory, developed independently by Derjaguin and Landau and Verwey and Overbeek. When a magnetic field is applied to magnetic particles, these particles experience additional attractionse along the direction of the external field and repulsions normal to the external field; as the consequence, chains are formed by magnetic particles.
Magnetic-field-induced collisions of magnetic particles areinvestigated via microscopic visualization system and digital image analysis in this work. The observed collision paths of particles were compared with simulation results obtained from trajectory analysis. Results suggest that the characteristic time decreases with increasing particle concentrations and increasing magnetic field strengths.It was also found that the trajectories of the particles in suspension are similar to those obtained numerically from trajectory analysis. Results also suggest that the angle between the particles centerline and the magnetic field direction affects shapes of both experimental and theoretical collision paths significantly.

1.Hiemenz, P. C.(1997) Principles of colloid surface chemistry, MARCEL
DEKKER, New York.
2.行政院環保署 (1993) 生態環境的惡行，智茂文化事業有限公司，第十三章，第46頁。
3.徐治平、林天賜 (1998) 膠體懸浮液的凝聚現象-DLVO理論，化工，第四十五卷，第二期，第14-22頁。
4.Derjaguin, B. V. and L. D. Landau (1941) Theory of stability of strongly
Charged lyophobic sols and of the adhesion of strongly charged particles
In solutions of electrolytes, Acta Physicochimca URSS, 14, 733-762.
5.Verwey, E. J. W. and J. Th. G. Overbeek (1948) Theory of the stability of
lyophobic colloids, Elsevier, Amsterdam.
6.London, L. D. and E. M. Liftshitz (1969) Statistical Physicals, Pergamon,
Oxford.
7.Hamaker, H. C. (1937) London-van der waals attraction between spherical
particles, Physica, 4, 1058-1072.
8.Fair, G. M., J. C. Geyer, and D. A. Okum (1968) Water purification and
waste water treatment and disposal, John Wiley and Sons：New York.
9.楊萬發 (2002) 水及廢水處理化學，茂昌出版社，第六章。
10.石濤 (2001) 環境化學，鼎茂出版社，第八章，第4頁。
11.Gouy, C. (1910) Suy la constitution de la charge e’lectrique a’la surface
d’um e’lectrolyte, Annals of Physics (Pairs) Serie 4, 9, 457-468.
12.Chapman, D. L. (1913) A contribution to the theory of electrocapillarity,
Philosophical magazine, 6, 475-481.
13.Stern, O. (1924) Zur theorie der’elektrolytischem doppelschicht, Annals
Electrochemical, 30, 508-526.
14.Tsouris, C. and T. C. Scott (1995) Flocculation of paramagnetic particles
in a magnetic field, Journal of Colloid and Interface Science, 171,
319-330.
15.Bell, G. M., S. Levins, and L.N. McCartney (1970) Approximate methods
of determining the double-layer free energy of interaction between two
charged colloidal spheres, Journal of Colloid and Interface Science, 33,
335-359.
16.Hogg, R., T. W. Healy, and D. W. Fuerstenau (1966) Mutual coagulation of
Colloidal dispersions, Transactions Faraday Society, 18, 1638-1651.
17.Zeichner, G. R. and W. R. Schowalter (1979) Effects of hydrodynamic and
Colloid forces on the coagulation of dispersions, Journal of Colloid and
Interface Science, 71, 237-253.
18.林榮義 (2000) 鋰離子電池材料鋰-鎳-氧化合物的結構與磁性研究，國立中央大學物理研究所碩士論文。
19.雷大同 (2002) 錳鋅鐵氧化物磁性流體之製備及分散研究，國立成功大學資源工程研究所碩士論文。
20.李玉華 (2003) 含碳化鐵(Fe3C)奈米磁顆粒之非晶質碳膜其微觀結構、磁物質與磁阻之研究，國立成功大學物理研究所博士論文。
21.賴耿陽 (1995) 磁記錄理論與實務，復漢出版社，第176頁。
22.謝芳生譯 (1997) 工程電磁學，東華書局，第九章。
23.Mondain-Monval, O., A. Espert, P. Omargee, J. Bibette, F. Lead-Calderon,
L. Philip, and J. F. Joanny (1998) Polymer-induced repulsive forces:
exponential scaling, Physics Review Letters, 80, 1778-1781.
24.Chikazumi, S. (1986) Physics of magnetism；John Wiley and Sons：New
York.
25.Chin, C. J., S. Yiacoumi, and C. Tsouris (2001) Probing DLVO forces
using interparticle magnetic forces：transition from secondary-minimum
To primary-minimum aggregation, Langmuir, 17, 6065-6071.
26.Svoboda, J. (1982) Magnetics flocculation and treatment of fine weakly
magnetic minerals, IEEE Transactions on Magnetics, 18, 796-801.
27.Fermigier, M. and A. P. Gast (1992) Structure evolution in a paramagnetic
latex suspension, Journal of Colloid and Interface Science, 154, 522-539.
28.Fermigier, M., H. E. Joanne and A. P. Gast (1994) Aggregation kinetics of paramagnetic colloidal particles, Journal of Chemical Physics, 102,
5492-5498.
29.Kantorovich, S. and A. O. Ivanov (2002) Formation of chain aggregates in magnetic fluids:an influence of polydispersity, Journal of Magnetism and Magnetic Materials, 252, 244-246.
30.Climent, E., M. R. Maxey, and G. E. Karniadakis (2004) Dynamics of
self-assembled chaining in magnetorheological fluids, Langmuir, 20,
507-513.
31.Chin, C. J., S. Yiacoumi, and C. Tsouris (2002) Agglomeration of
magnetic particles and breakup of magnetic chains in surfactant solutions, Colloids and surface A：Physicochemical and Engineering Aspects, 204, 63-72.
32.Smoluchowski, M. (1934) Versuch einer mathematischen theovie der
koagulationskinetic kolloider losungen, Zeitschrift fuer Physik Chemical,
92, 129-168.
33.Fuchs, N. (1934) Uber die stabilitat und aufladung der aerosloe, Zeitschrift fuer Physik, 89, 736-743.
34.Russel, W. B., D. A. Saville and W. R. Schowalter (1989) Colloidal
Dispersions, Cambridge, Univ.Press, London/New York.
35.Zhou, Z. and B.Chu, (1991) Light-scattering study on the fractal
aggregates of polystyrene spheres: Kinetic and structural approaches,
Journal of Colloid and Interface Science, 143, 356-365.
36.Burns, J. L., Y. Yun, G. J. Jameson, and S. Biggs (1997) A Light
Scattering Study of the Fractal Aggregation Behavior of a Model Colloidal System, Langmuir, 13, 6413-6420.
37.Kim, A. Y. and J. C. Berg (2000) Fractal Aggregation：scaling of fractal
dimension with Stability Ratio, Langmuir, 16, 2101-2104.
38.Janssen, J. J. M., J. M. Baltussen, A. P. van Gelder and J. A. A. J.
Perenboom (1990) Kinetics of magnetic flocculation. I. Flocculation of colloidal particles, Journal of Physics D-Applied Physics, 23, 1447-1454.
39.Bossis, G., C. Mathis, Z. Mimouni, and C. Paparoditis (1990)
Magnetoviscosity of micronic suspensions, EurophysicsLetters, 11,
133-137.
40.Shell, W. (1931) Staubausscheidung en einfachen Koerpern in Luftiltern,
Verein Deutscher Ingenieure Forschungsheft, 347.
41.O’Melia, C. R. and Stumm, W. (1967) Theory of water filtration, Journal
of American Water Association, 59, 1393-1412.
42.Yao, K. M. (1968) Influence of suspended particle size on the transport aspect of water filtration,PhD Dissertation, University of North Carolina, Chapel Hill, North Carolina.
43.Van der ven, T. G. M. and S. G. Mason (1977) The microrheology of
colloidal dispersions：orthokinetic doublet formation of spheres, Colloid
Polymer Science, 255, 468-479.
44.Kobayashi, M., T. Maekita, Y. Adachi, and H. Sasaki (2004) Colloid
stability and coagulation rate of polystyrene latex particles in a turbulent
flow, International Journal of Mineral Processing, 73, 177-181.
45.Zhang, X. and R. H. Davis (1991) Polarized optical microscopy of
anisotropic media. Imaging theory and simulation, Journal of
Fluid Mechanics, 230, 479-500.
46.Elimelech, M. ,J. Gregory, X. Jia, and R. A. Williams (1998) Particle
deposition ＆Aggregation：measurement,modeling and simulation, BUTTER-WORTH HEINEMANN, 138-142.
47.Tsouris, C., S. Yiacoumi, and D. A. Rountree (1996) Mechanism of
Particle flocculation by magnetic seeding, Journal of Colloid and
Interface Science, 184, 1-12.
48.Batchelor, G. K. and J. T. Green (1972) The hydrodynamic interaction of
two small freely-moving spheres in a linear flow field, Journal of Fluid Mechanics, 56, 375-400.
49.Chin, C. J., S. Yiacoumi, and C. Tsouris (2000) Secondary-minimum
aggregation of superparamagnetic colloidal particles, Langmuir, 16,
3641-3650.
50.葉政男 (1997) 磁場產生器之設計與製作及磁阻元件特性量測，國立中央大學機械研究所碩士論文。
51.王以真 (1995) 實用磁路設計，全華科技圖書公司，第八章。