Presenter: Dr. Jeffrey J. Schwartz (University of California, Los, Angeles）
Topic: What’s on The Outside Counts Too: Surface-Dipole Modulated Assembly
Time: 10:00 AM, Feb. 22th (Wednesday)
Location: Conference Room B, BLDG 909-1F
Abstract
Detailed understanding and control of the intermolecular forces that govern molecular assembly are necessary to engineer structure and function at the nanoscale. Liquid crystal (LC) assembly is exceptionally sensitive to surface properties, capable of transducing nanoscale intermolecular interactions into a macroscopic optical readout. Self-assembled monolayers (SAMs) modify surface interactions and are known to influence LC alignment. Here, we exploit the different dipole magnitudes and orientations of carboranethiol and -dithiol positional isomers to deconvolve the influence of SAM-LC dipolar coupling from variations in molecular geometry, tilt, and order. Director orientations and anchoring energies are measured for LC cells employing various carboranethiol and -dithiol isomer alignment layers. The normal component of the molecular dipole in the SAM, toward or away from the underlying substrate, was found to determine the in-plane LC director orientation relative to the anisotropy axis of the surface. By using LC alignment as a probe of interaction strength, we elucidate the role of dipolar coupling of molecular monolayers to their environment in determining molecular orientations. We apply this understanding to advance the engineering of molecular interactions at the nanoscale.
Biography:
EDUCATION
Doctor of Philosophy(Ph.D.), Physics
University of California, Los Angeles 2009-2016
Advisor: Paul S. Weiss
Master of Science(M.S.), Physics 2009-2010
University of California, Los Angeles
Bachelor of Science(B.S.), Physics
The University of Texas at Dallas 2005-2009
Minor: Mathematics
PUBLICATIONS
Surface Dipole Control ofLiquid Crystal Alignment. Jeffrey J. Schwartz, Alexandra M.Mendoza, Natcha Wattanatorn, Yuxi Zhao, Vinh Nguyen, Alexander M. Spokoyny, Chad A.Mirkin, Toma´sˇ Basˇe, and Paul S. Weiss, J. Am. Chem. Soc. 138, 5957 (2016).
Defect-Tolerant Aligned Dipoles within Two-Dimensional Plastic Lattices. John C. Thomas, Jeffrey J. Schwartz, J. Nathan Hohman, Shelley A. Claridge, Harsharn S. Auluck, Andrew C. Serino, Alexander M. Spokoyny, Giang Tran, Kevin F. Kelly, Chad A. Mirkin, Jerome Gilles
Differentiating Amino Acid Residues and Side Chain Orientations in Peptides Using Scanning Tunneling Microscopy. Shelley A. Claridge, John C. Thomas, Miles A. Silverman, Jeffrey J.Schwartz, Yanlian Yang, Chen Wang, and Paul S. Weiss, J. Am. Chem. Soc. 135, 18528
Molecular Flux Dependence of Chemical Patterning by Microcontact Printing. Jeffrey J.Schwartz, J. Nathan Hohman, Elizabeth I. Morin, and Paul S. Weiss, ACS Appl. Mater.
Electrons, Photons, and Force: Quantitative Single-Molecule Measurements from Physics to Biology. Shelley A. Claridge, Jeffrey J. Schwartz, and Paul S. Weiss, ACS Nano5, 693
Field Emission Properties ofZnO, ZnS and GaN Nanostructures. Y. Mo, J. J. Schwartz, M. H. Lynch, P. A. Ecton, A. Neogi, J. M. Perez, Y. Fujita, H. W. Seo, Q. Y. Chen, L. W.Tu, and N. J. Ho, in Nanoscale Photonics and Optoelectronics, edited by Z. M. Wang and A.
Contact: Prof. Lifeng Chi