Some References: Colloids – A lot of what I presented is in -"Thermodynamics and Hydrodynamics of Hard Spheres; the role of gravity.", P. M. Chaikin, in Soft and Fragile Matter, Nonequilibrium Dynamics, Metastability and Flow, ed. By M. E. Cates and M. R. Evans, (Institute of Physics Publishing, London, 2000) and there are more general references and it is a good volume. Some of our stuff: Z. Cheng, W.B. Russel, and P.M. Chaikin "Controlled growth of hard-sphere colloidal crystals", Nature 401, (1999). "Crystallization Kinetics of Hard Spheres in Microgravity in the Coexistence Regime: Interactions between Growing Crystallites", Zhengdong Cheng, P. M. Chaikin, Jixiang Zhu, W. B. Russel, and W. V. Meyer, Phys. Rev. Lett. {\bf 88}, (2002). "Colloidal hard-sphere crystallization kinetics in microgravity and normal gravity", ZD Cheng,JX Zhu,WB Russel,WV Meyer,PM Chaikin,APPLIED OPTICS {\bf 40}, (2001). "Phase diagram of hard spheres", Cheng Z, Chaikin PM, Russel WB, Meyer WV, Zhu J, Rogers RB, Ottewill RH, MATERIALS \& DESIGN,{\bf 22}, (2001). Phonons in an Entropic Crystal Zhengdong Cheng, Jixiang Zhu, William B. Russel, P. M. Chaikin, Phys. Rev. Lett. 85, 1460 (2000) Nature of the divergence in low shear viscosity of colloidal hard-sphere dispersions, Cheng ZD, Zhu JX, Chaikin PM, Phan SE, Russel WB, PHYSICAL REVIEW E65 (4): art. no Part 1 APR 2002 Good diblock references: F. S. Bates, and G. H. Fredickson, Physics Today Feb, 1999 F. S. Bates, Science, 251, 898 Some of our stuff is in: C. Harrison, D.H. Adamson, Z. Cheng, J.M. Sebastian, S. Sethuraman, D.A. Huse, R.A. Register, and P.M. Chaikin, "Mechanisms of Ordering in Striped Patterns", Science, 290, (2000). R. R. Li, P. D. Dapkus, M. E. Thompson, W. G. Jeong C. Harrison, P. M. Chaikin, R. A. Register,D. H. Adamson, Dense Arrays of Ordered GaAs Nanostructures by Selective Area Growth on Substrates Patterned by Block Copolymer Lithography, APPL PHYS LETT 76: (13) (2000)

Diblock Copolymer Nanolithography Lamellae Cylinders Spheres

Monolayers on a substrate

collaboration with R.R. Li, P.D. Dapkus, and M.E. Thompson (USC)  use MOCVD to selectively grow GaAs dots on substrate, through holes in removable “mask” GaAs ozone CF 4 RIE MOCVD wet etch polymer SiN x (15 nm) GaAs

height above SiN x (TMAFM) dot diameter (FESEM) GaAs (001) TMAFM tip GaAs Dots Have Narrow Size Distribution Size (nm) Number of Dots diameter: 23 ± 3 nm overall height: 14 ± 2 nm tapping-mode atomic force microscopy (TMAFM)

Orientational Correlation lengthAverage Distance between Disclinations  2 ~  -1/2  t 1/4   466 K 395 K

Fred, 0.5 point blur. Figure 2. AB C 500 nm D DEPTH PROFILING AN ISLAND MIDDLETOP BOTTOM

Nature Feb. 6,1965 Topological equivalent For Circular area two loops are essential Two Loops Three loops and one Triradius

Disclinations : “5” and “7” Analysis of a micrograph 100 nm 0  /3 Steps : 1.Locate Spheres 2.Triangulate Lattice 3.Locate disclinations 4.Locate dislocations 5.Create orientation field 6.Color-map

Measuring Correlation Length  6 All sphere centers are located and the inter-sphere triangulation lattice produces the local “bond-orientation” angle. We define e 6i  (x) as our hexatic order parameter to calculate  6, similar to  2.   ~130 nm~4.5 d nm Correlation Function Images

e:\papers\hexaticcoarsening\master 1 Time Dependence of Correlation Length t 1/4 shift data by a T, taking 398K as reference t/a T (nm)

Color Lookup Table 40nm Step Edge dislocations

“perfect alignment with Mask and Pressure Substrate Without mask Mask Substrate With mask PS/PI S. Chou C. Harrison, P. Chaikin, & R. Register

Effect of Diblock Copolymers on the Quantum Hall Effect The periodic modulation induced by the triangular polymer lattice lifts the degeneracy of the Landau levels, creating a commensurability-related sub-band structure (Hofstadter butterfly) which should cause extra peaks to appear in the longitudinal resistance. Hall Resistance R xy (k  ) Longitudinal Resistance R xx (k  ) Magnetic Field B (T) T=0.3K unpatterned Longitudinal Resistance R xx (k  ) Magnetic Field B (T) T=0.3K patterned V g =0.1 Chaikin, Register, Shayegan, Bhatt a 1  m