Bulletin of the American Physical Society
APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014; Denver, Colorado
Session D18: Cleverly Creating Colloidal Clusters |
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Sponsoring Units: GSNP DCMP Chair: Kazem Edmond, New York University Room: 403 |
Monday, March 3, 2014 2:30PM - 2:42PM |
D18.00001: Three-Dimensional Lock and Key Colloids Yu Wang, Yufeng Wang, Xiaolong Zheng, Gi-Ra Yi, Stefano Sacanna, David Pine, Marcus Weck Colloids based upon silica patchy particles featuring a (trimethoxysilyl)propyl methacrylate matrix are synthesized. Selective etching of the silica patches results in the controllable fabrication of colloids with three-dimensional multicavities. The obtained hollow particles exhibit depletion interaction-driven self-assembly with polystyrene spheres in the presence of poly(ethylene oxide), demonstrating for the first time three-dimensional lock and key colloids. [Preview Abstract] |
Monday, March 3, 2014 2:42PM - 2:54PM |
D18.00002: Study of cluster formation in a quasi-square well model of Janus ellipsoids Donovan Ruth, Jeffrey Rickman, James Gunton, Wei Li We investigate the effect of geometry and range of attractive interaction on the self-assembly of Janus particles. In particular, we consider Janus spheroids with an aspect ratio of 0.6 and a quasi-square well model with a short range attractive interaction of 0.2 sigma where sigma is the characteristic length of the spheroid. We find that below a certain transition temperature the system forms orientationally ordered micelles and vesicles, with a cluster distribution qualitatively similar to that found in an earlier study of Janus spheres. (Phys. Chem. Chem. Phys. (2010) vol 12, 11869-11877, F. Sciortino, A. Giacometti and G. Pastore) Finally we discuss the implications of our work for encapsulation by self-assembly. [Preview Abstract] |
Monday, March 3, 2014 2:54PM - 3:06PM |
D18.00003: Shape Memory Colloidal Assemblies of Janus Ellipsoids Benjamin Schultz, Aayush Shah, Wenjia Zhang, Michael Solomon, Sharon Glotzer AC electric and magnetic fields have been widely used to create reconfigurable chains of uniform and patchy colloidal particles that can be used to create switchable, anisotropic electronic and elastic responses in bulk media. Here, we report a joint experimental and computational study of the self and directed assembly of patchy ellipsoidal particles that combine both shape and interaction anisotropy. These particles are synthesized by sequentially combining evaporative deposition of chrome and gold with the uniaxial deformation of polymeric colloidal particles. We explore the self assembly behavior of these particles into clusters and one dimensional chains as a function of salt concentration and aspect ratio. From computational studies, we identify the minimal interactions required to reproduce experimentally observed structures and mechanisms driving chain growth. Upon the application of an AC electric field, we exploit the asymmetric polarizability of these particles to assemble chain structures with new morphologies. We are able to reconfigure between AC field and equilibrium self assembly structures, enabling the actuation of self assembled chains for rapid switching rates and accelerating chain growth for slow switching rates. [Preview Abstract] |
Monday, March 3, 2014 3:06PM - 3:18PM |
D18.00004: Self-assembly with and of patchy colloids: prediction and exploration Erik Edlund, Oskar Lindgren, Martin Nilsson Jacobi Patchy colloids serve as one of the key models for self-assembly of anisotropic building blocks. Interestingly, it is possible to use self-assembly to create the patchy colloids themselves [1]. We present recently developed theory for predicting pattern formation on colloids [2] and suggests a systematization of such self-assembled patchy colloids. This allows us to perform systematic computational study of patchy particles and their self-assembly into complex structures, results from which we present here. Our results highlight the importance of interplay between theory and computational exploration. [1] A. M. Jackson, J. W. Myerson, and F. Stellacci, Nat. Mater. 3(5), 330 (2004) [2] E. Edlund, O. Lindgren., and M. Nilsson Jacobi, (2013) http://arxiv.org/abs/1310.3858 [Preview Abstract] |
Monday, March 3, 2014 3:18PM - 3:30PM |
D18.00005: A path to designing self-assembling surface patterns on particles for self-assembly of the particles themselves Oskar Lindgren, Erik Edlund, Martin Nilsson Jacobi Patchy colloids are promising candidates for self-assembly of metamaterials since directional attraction and high specificity reduces the ambiguity of the low energy state, this simplifies the design of self-assembling building blocks. However, the large scale fabrication of colloids with specific patterns becomes more difficult as the complexity of the surface pattern increases. Self-organiziation of the surface patterns themselves have been suggested as a promising fabrication method due to the new types of patterns it makes accessible. We present a method for designing self-assembling patterns in multiple components system on particle surfaces. The method is based on an analytical treatment of an effective interaction representation of real systems. As an example, we use a simplified model of Alkalethoils-on-gold to show how a limited amount of system parameters can be tuned in order to cause self-assembly of desired surface patterns. We perform in silico self-assembly of surface patterns on spherical colloids, the patterns then causes the colloids themselves to self-assemble into various geometric target structures like strings, membranes, cubic aggregates and lattices. [Preview Abstract] |
Monday, March 3, 2014 3:30PM - 3:42PM |
D18.00006: Non-equilibrium self-assembly of ``sticky'' colloidal particles under alternating electric field Alexey Snezhko, Arnaud Demortiere, Igor Aranson Ensembles of interacting colloidal particles subject to an external periodic forcing often develop nontrivial self-assembled phases. We study emergent phenomena in partially cross-linked colloidal ensembles of epoxy particles driven out of equilibrium by alternating magnetic fields in a nonpolar solvent. We report on the discovery of self-assembled tunable networks of microscopic polymer fibers ranging from wavy colloidal ``fur'' to highly interconnected networks. The networks emerge via dynamic self-assembly in an alternating (ac) electric field from a non-aqueous suspension of ``sticky'' polymeric colloidal particles with a controlled degree of polymerization. The resulting architectures are tuned by the frequency and amplitude of the electric field and surface properties of the particles. The research was supported by the U.S. DOE, Office of Basic Energy Sciences, Division of Materials Science and Engineering, under the Contract No. DE AC02-06CH11357 [Preview Abstract] |
Monday, March 3, 2014 3:42PM - 3:54PM |
D18.00007: Structural phases of trapped colloids with competing interactions in two and three dimensions S\'ergio Wlademir da Silva Apolin\'ario, Lucas de Queiroz da Costa Campos, Everton Oliveira Lima, Hartmut L\"owen By employing Brownian dynamics simulation we analyzed the spatial configurations resulting from a self-assembly process of colloidal particles interacting via a competive isotropic pair potential both in two and three dimensions. A wide variety of different spacial configurations is found to be stable which includes, for two dimensions, clusters with a fringed outer rim (reminiscent to an ornamental border), clusters perforated with voids as well as clusters with a crystalline core and a disordered rim, and, for three dimensions, clusters perforated with channels and helical fringes. All cluster structures occur in a two-dimensional parameter space. The structural ordering can therefore be efficiently tuned by changing few parameters only providing access to a controlled fabrication of colloidal clusters. [Preview Abstract] |
Monday, March 3, 2014 3:54PM - 4:06PM |
D18.00008: Equilibrium distribution of symmetric self-assembled structures Henrik van Lengerich, John Spohn, Richard James Many self-assembled structures are symmetric and are composed of identical subunits. The assembled structure depends not only on subunit position, but also on orientation, (ie. virus capsids, Janus particles, and liquid crystals). We find the equilibrium distribution of various symmetric self-assembly systems by enumerating all possible clusters. The degeneracy of the minima depends on the symmetry of the cluster. Theoretical results are compared with numerical simulations of the Langevin equation and macroscopic experiments. The validity of this comparison is proven by deriving the Smoluchowski equation for interacting elements that depend on orientation. [Preview Abstract] |
Monday, March 3, 2014 4:06PM - 4:18PM |
D18.00009: DNA Origami Functionalized Colloids Matan Yah Ben Zion, Corinna Maass, Kunta Wu, Ruojie Sha, Ned Seeman, Paul Chaikin The design of self assembled colloids is limited by their spherical symmetry which gives rise to a spectrum of rotomers instead of a unique structure. We propose functionalizing colloids with DNA Origami which can speci cally bind to one another at a nanometric resolution in a prede ned angle using DNA sticky ends hybridization. As DNA Origami is a mesoscopic entity in its nature, with a typical size of $\sim$100nm, it is a natural candidate for mediating interactions between microscopic particles such as colloids. Using an elongated belt-like design we show for the first time specific binding between colloids by the Origami. It is also possible to control the binding orientation by aligning the sticky ends on the origami in a prochiral pattern creating new opportunities in colloidal self assembly. [Preview Abstract] |
Monday, March 3, 2014 4:18PM - 4:30PM |
D18.00010: An Automated Microfluidic Chemostat for a Self-Replicating System of DNA Constructs Andrew Bergman, Xiaojin He, Corinna Maass, Ruojie Sha, Yongli Mi, Nadrian Seeman, Paul Chaikin We have modified a bacterial microchemostat$^{\mathrm{1}}$ for use in studying and optimizing a self-replicating system based on DNA constructs. The self-replication process we employ requires cycling temperature and UV light exposure. The base units of our system are DNA constructs that can recognize their complements using DNA ``sticky ends'' and can be covalently linked to one another through the use of a UV-crosslinkable nucleobase substitute. ``Seed particles'' of varying length are made by attaching two or more of these constructs and are added to and processed in this microfluidic system, which allows for temperature control, UV illumination and microscopic observation of fluorescence and FRET. Automation provides for a well-regulated and high-throughput testing and optimization of conditions. [1] F. K. Balagadde \textit{et al.}, Science \textbf{309}, 137 (2005). [Preview Abstract] |
Monday, March 3, 2014 4:30PM - 4:42PM |
D18.00011: Programming colloidal phase transitions with DNA strand displacement William Rogers, Vinothan Manoharan Specific interactions induced by transient bridging of complementary DNA strands grafted to colloidal particles can direct assembly of nanostructured materials. These interactions have been used to `program' the symmetry of novel equilibrium superlattices and could in principle enable self-assembly of prescribed structures. However, the ability to program the \textit{transitions} between these equilibrium phases is currently limited: DNA-mediated attractions between particles decrease monotonically and steeply with increasing temperature, resulting only in high-temperature fluids and low-temperature solids that are inherently difficult to equilibrate. We show that by introducing free DNA strands that compete to bind with the grafted ones by strand displacement, the temperature dependence of interparticle interactions can be programmed through the base sequences of displacing strands. We use this scheme to create colloids with `designer' phase behavior such as re-entrant melting, arbitrarily wide gas-solid coexistence, and reversible transitions between different binary crystals. [Preview Abstract] |
Monday, March 3, 2014 4:42PM - 4:54PM |
D18.00012: Programmable Sequential Assembly in a DNA Functionalized Emulsion System Yin Zhang, Lea-Laetitia Pontani, Martin Haase, Lang Feng, Ruojie Sha, Nadrian Seeman, Jasna Brujic, Paul Chaikin Assembling a complex structure requires not only the appropriate association of specific units, but putting the pieces together sequentially in the right order. We present the sequential self-assembly of a system of micron-sized emulsion droplets functionalized by pre-programmed DNA molecules. Each droplet is initially inert with the DNA protected by a partially complementary strand with a toehold. A Yurke process [1] utilizes the toehold to free the protected strand which can then act in a similar way to bind to the toehold on the next droplet in the sequence and deprotect a strand which continues the reaction to subsequent droplets. Since the DNA attached to a lipid on an emulsion is mobile this design enables the cyclic strand displacement on the nanoscale to produce sequence-specific interactions on the microscale. We demonstrate such programmed assembly in a system of three types of droplets with different cyclically complementary protected strands. \\[4pt] [1] B. Yurke et al., Nature, 406, 605-608(2000) [Preview Abstract] |
Monday, March 3, 2014 4:54PM - 5:06PM |
D18.00013: Self-replicating devices with dipolar colloids Joshua Dempster, Rui Zhang, Monica Olvera de la Cruz Ubiquitous in nature, self-replication on the nano-scale has been challenging to produce in the laboratory. Recent efforts with DNA tiles have shown great success in correctly replicating tile-sequence templates but require frequent manipulation by the experimenter. We propose a scheme for achieving self-replication with dipolar colloids. Dimers in these systems replicate exponentially over millisecond time scales with no intervention other than periodic energy pulses supplied by external fields. We develop a general formalism governing the rate of self-replication as a function of the interval between pulses. Results from kinetic Monte Carlo simulations show good agreement with the growth rates predicted by simple models of the replication process. [Preview Abstract] |
Monday, March 3, 2014 5:06PM - 5:18PM |
D18.00014: Remembering a Shape --- Assembling a Memory Zorana Zeravcic, Arvind Murugan, Michael Brenner, Stanislas Leibler Recently we have been developing a new connection between self-assembly and neural networks, where a multi-component particle system with specified interaction rules between its components is mapped onto a multi-state Hopfield neural network model. Within this framework, a fixed interaction pattern of neurons representing a ``memory'' maps to particle interactions encoding a certain structure. Properties of neural networks motivate new types of questions: Can the interaction energies of particles code for multiple structures at the same time? Can stored structures be retrieved by throwing in a nucleation seed (i.e., a small assembly of particles) and have it complete into the desired stored structure? Can we define a capacity, i.e., a maximal number of structures that can be retrieved with limited error? We investigate these questions using numerical simulations of different types of building blocks with short-range interactions. [Preview Abstract] |
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