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Rainbows in a vial: controlled assembly of 2D colloids in two perpendicular external fields
被引:15
|作者:
Chen, Mingfeng
[1
]
Shinde, Abhijeet
[2
]
Wang, Ling
[2
,5
]
Ye, Chong
[1
]
Zeng, Minxiang
[2
]
Yan, Qi
[1
]
Lin, Pengcheng
[1
]
Chen, Ying
[1
]
Cheng, Zhengdong
[2
,3
,4
]
机构:
[1] Guangdong Univ Technol, Sch Mat & Energy, Soft Matter Ctr, Guangdong Prov Key Lab Funct Soft Condensed Matte, Guangzhou 510006, Guangdong, Peoples R China
[2] Texas A&M Univ, Artie McFerrin Dept Chem Engn, College Stn, TX 77843 USA
[3] Texas A&M Univ, Artie McFerrin Dept Chem Engn, Mary Kay OConnor Proc Safety Ctr, College Stn, TX 77843 USA
[4] Texas A&M Univ, Mat Sci & Engn, College Stn, TX 77843 USA
[5] Tianjin Univ, Sch Mat Sci & Engn, Tianjin 300350, Peoples R China
来源:
2D MATERIALS
|
2019年
/
6卷
/
02期
关键词:
2D colloids;
monodomain;
magnetic field;
interference color band;
EQUATION-OF-STATE;
CRYSTAL PHASE-TRANSITIONS;
OXIDE LIQUID-CRYSTALS;
ZIRCONIUM-PHOSPHATE;
POLYDISPERSITY;
SEDIMENTATION;
DISPERSIONS;
MONODOMAIN;
D O I:
10.1088/2053-1583/ab0581
中图分类号:
T [工业技术];
学科分类号:
08 ;
摘要:
The ability to control the dynamics of self-assembly of an isotropic nanoparticles over multiple length scales by application of external fields is an important technological and fundamental challenge in colloidal science and soft condensed matter physics. Here we demonstrate the controlled assembly of two-dimensional (2D) colloidal liquid crystals under the influence of gravity and an external magnetic field. Due to the positive anisotropy of diamagnetic susceptibility (Delta chi > 0), the colloidal nanoplates of monolayer zirconium phosphate could exhibit intriguing alignment with their normals parallel to the magnetic field, thus transforming the multi-domain nematic phase into a mono-domain superstructure. Interestingly, the quasi-equilibrium states of such 2D soft materials under the prolonged gravity-induced sedimentation were found to generate a rich pattern of interference color bands (referred to as rainbows in a vial) upon under the effect of an aligning magnetic field. The birefringence measurement of the resulting color bands suggested quadratically decreasing volume fraction with sample height. The osmotic pressure (Pi) as a function of nanoplate volume fraction (phi) is found to agree with the theoretical prediction of the equation of state of the nematic phase of hard nanoplates, with a positive deviation at higher volume fractions. To the best of our knowledge, such field-driven dynamic formation of rich interference color bands, imitating almost the full spectrum of Michel-Levy interference bands, which was a pure mathematical representation, is experimentally achieved for the first time in a single sample.
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页数:11
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