Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session Q39: Focus Session: Polymer Nanocomposites - Active Particles and Dynamics |
Hide Abstracts |
Sponsoring Units: DPOLY Chair: Jacinta Conrad, University of Houston Room: 213AB |
Wednesday, March 4, 2015 2:30PM - 2:42PM |
Q39.00001: Vertical Diblock Copolymer Cylinder-Nanorod Nanocomposites Boris Rasin, Huikuan Chao, Xingchen Ye, Yaoting Wu, Jeffrey Meth, Christopher Murray, Robert Riggleman, Russell Composto Nanocomposites consisting of nanorods in a diblock copolymer film with a vertical cylinder structure are investigated. The diblock copolymer film is poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) with vertical P2VP cylinders in a PS matrix. The nanorods in the PS-b-P2VP film are gold nanorods functionalized with a variety of ligands. The nanocomposite film is prepared by spin-coating and solvent annealing a solution of PS-b-P2VP and gold nanorods. The position and orientation of the gold nanorods in the PS-b-P2VP film is studied as system parameters are varied. Parameters varied include nanorod dimensions, nanorod concentration and the ligand with which the nanorods are functionalized. Field theoretic simulations are used to guide the experiments and interpret the results. [Preview Abstract] |
Wednesday, March 4, 2015 2:42PM - 2:54PM |
Q39.00002: Photothermal Heating via Gold Nanorods within Polymer Nanocomposites Jason Bochinski, Somsubhra Maity, Wei-Chen Wu, Joseph Tracy, Laura Clarke Metal nanoparticles under continuous-wave (cw) optical excitation resonant with their localized surface plasmon exhibit a photothermal effect, efficiently converting the incident light into heat [1] originating from the particle. Gold nanorods (GNRs) dispersed within a transparent material are utilized as such remotely-controlled, nano-sized heaters [2], with heating properties which can be manipulated and monitored by using control of the polarization direction [3, 4] of the excitation and probe light fields. Steady-state average temperatures within a polymer matrix embedded with GNRs undergoing cw photothermal heating are determined in the immediate vicinity of the GNR by observing the rate of driven physical rotation of the nanorods, and simultaneously across the entire sample by using an independent fluorescence method. Comparing these two observations as the concentration of dispersed GNRs is varied reveals the interplay between local and global heating in these polymer nanocomposite materials.\\[4pt] [1] S. Maity et al., \textit{Polymer} \textbf{52}, 1674 (2011).\\[0pt] [2] S. Maity et al., \textit{Adv. Funct. Mater.} \textbf{22}, 5259 (2012).\\[0pt] [3] S. Maity et al., \textit{Part. \& Part. Sys. Char.} \textbf{30}, 193 (2013).\\[0pt] [4] S. Maity et al., \textit{Nanoscale} \textbf{in press}, (2014) [Preview Abstract] |
Wednesday, March 4, 2015 2:54PM - 3:06PM |
Q39.00003: Utilizing Fiber-containing Thermo-responsive Gels to Extract Nanoparticles from Solution Ya Liu, Olga Kuksenok, Anna Balazs Using computer simulations, we model an array of flexible fibers that are embedded in a lower critical solution temperature (LCST) thermo-responsive gel, which swells at lower temperatures and collapses at higher temperatures. The system is immersed in a solution containing dispersed nanoparticles and this fluid is driven to flow by an imposed shear. When the gel is heated, it collapses to expose the fibers, and thereby, triggers the ``catch'' process. Namely, the fibers can act like ``arms'' that wrap around the nanoparticle and bring it from the outer solvent into the gel layer. Moreover, we show that depending on the flexibility and hydrophobicity of the fibers, as well as the imposed shear, we can position the nanoparticles at the desired height within the gel layer. Our approach can be utilized for the detection and separation of components in fluids and for the controlled insertion of nanoparticles within a hydrogel at a particular distance from the gel interface [Preview Abstract] |
Wednesday, March 4, 2015 3:06PM - 3:18PM |
Q39.00004: Photothermal heating as a methodology for post processing of polymeric nanofibers Russell Gorga, Laura Clarke, Jason Bochinski, Vidya Viswanath, Somsubhra Maity, Ju Dong, Gabriel Firestone Metal nanoparticles embedded within polymeric systems can be made to act as localized heat sources thereby aiding in-situ polymer processing. This is made possible by the surface plasmon resonance (SPR) mediated photothermal effect of metal (in this case gold) nanoparticles, wherein incident light absorbed by the nanoparticle generates a non-equilibrium electron distribution which subsequently transfers this energy into the surrounding medium, resulting in a temperature increase in the immediate region around the particle. Here we demonstrate this effect in polymer nanocomposite systems, specifically electrospun polyethylene oxide nanofibrous mats, which have been annealed at temperatures above the glass transition. A non-contact temperature measurement technique utilizing embedded fluorophores (perylene) has been used to monitor the average temperature within samples. The effect of annealing methods (conventional and photothermal) and annealing conditions (temperature and time) on the fiber morphology, overall crystallinity, and mechanical properties is discussed. This methodology is further utilized in core-sheath nanofibers to crosslink the core material, which is a pre-cured epoxy thermoset. [Preview Abstract] |
Wednesday, March 4, 2015 3:18PM - 3:30PM |
Q39.00005: Modeling Stimuli-Responsive Nanoparticle Monolayer Xin Yong Using dissipative particle dynamics (DPD), we model a monolayer formed at the water-oil interface, which comprises stimuli-responsive nanoparticles. The solid core of the nanoparticle encompasses beads arranged in an fcc lattice structure and its surface is uniformly grafted with stimuli-responsive polymer chains. The surface-active nanoparticles adsorb to the interface from the suspension to minimize total energy of the system and create a monolayer covering the interface. We investigate the monolayer formation by characterizing the detailed adsorption kinetics. We explore the microstructure of the monolayer at different surface coverage, including the particle crowding and ordering, and elucidate the response of monolayer to external stimuli. The collective behavior of the particles within the monolayer is demonstrated quantitatively by vector-vector autocorrelation functions. This study provides a fundamental understanding of the interfacial behavior of stimuli-responsive nanoparticles. [Preview Abstract] |
Wednesday, March 4, 2015 3:30PM - 3:42PM |
Q39.00006: Using Gold Nanorods to Probe the Local Environment within Polymer Nanocomposites Laura Clarke, Somsubhra Maity, Wei-Chen Wu, Joseph Tracy, Jason Bochinski Active metal nanoparticles embedded within polymeric materials can generate internal photothermal heating [1,2] to enable processing, such as shape memory actuation [3] or thermal annealing [4], with outcomes unrealizable by conventional means. When gold nanorods are utilized [5, 6], their anisotropic-shape provides additional capabilities: using the nanoparticle as an optical probe allows quantitative measurement of the local polymer environment, particularly in the melt phase. Specifically, one surface plasmon excitation can heat while the other monitors particle orientation (altered by rotational diffusion) to make a temperature measurement in the region near the nanorod [6]. We describe results from this approach along with examples of the differing local environments within the polymer due to changes in processing.\\[4pt] [1] S. Maity et al., \textit{Polymer} \textbf{52}, 1674 (2011).\\[0pt] [2] S. Maity et al., \textit{Adv. Funct. Mater.} \textbf{22}, 5259 (2012).\\[0pt] [3] D. B. Abbott et al., \textit{Macromolecular Chemistry and Physics} \textbf{in press}, (2014).\\[0pt] [4] V. Viswanath et al., \textit{Macromolecules} \textbf{46}, 8596 (2013).\\[0pt] [5] S. Maity et al., \textit{Part. \& Part. Sys. Char.} \textbf{30}, 193 (2013).\\[0pt] [6] S. Maity et al., \textit{Nanoscale} \textbf{in press}, (2014). [Preview Abstract] |
Wednesday, March 4, 2015 3:42PM - 3:54PM |
Q39.00007: Contrasting nanoparticles diffusion in synthetic and biopolymer solutions Sharmine Alam, Indermeet Kohli, Ashis Mukhopadhyay We investigated the dynamics of gold nanospheres (AuNS) and nanorods (AuNR) in synthetic polymer (polyethylene glycol) and biopolymer (bovine serum albumin and mucin) solutions. The variables are particle size and shape, polymer volume fraction, etc. The fluctuation correlation spectroscopy (FCS) was used to measure the translational (D$_{\mathrm{T}})$ and rotational diffusion (D$_{\mathrm{R}})$ of gold nanoparticles. Comparison will be made for the nano-viscosities at different length scales. The nanoparticle dynamics within the mucus gel will be presented. [Preview Abstract] |
Wednesday, March 4, 2015 3:54PM - 4:06PM |
Q39.00008: Embedded Gold Nanorods as Microscale Thermochromic Temperature Sensors W. Joshua Kennedy, Keith Slinker, Hilmar Koerner, Gregory Ehlert, Jeffery Baur Gold nanorods (AuNRs) are known to undergo a shape transformation via surface melting at temperatures far below the bulk melting temperature of gold. Because the optical scattering by the AuNRs depends on both particle morphology and the surrounding local dielectric constant the opto-thermal properties of polymer-AuNR nanocomposites depend strongly on the chemical and mechanical characteristics of the polymer host. We have measured the optical absorption of polymer nanocomposites consisting of AuNRs in a variety of polymer systems as a function of temperature, time, molecular weight, and crosslink density. Our results show that the shape transformation of the AuNRs is not well described by a simple kinetic model, and that multiple contributors to the surface energy play significant roles in the process. We show that the dynamics of the shape transformation may be calibrated in a nanocomposite such that the optical absorption spectrum of the material may be used as a local sensor of both temperature history and degree of cure. We demonstrate the usefulness of this technique by measuring (ex situ) the temperature of an internally heated epoxy resin with a lateral spatial resolution of $<10$ $\mu$m. [Preview Abstract] |
Wednesday, March 4, 2015 4:06PM - 4:18PM |
Q39.00009: Supramolecular Nanocomposites Under Confinement: Chiral Optically Active Nanoparticle Assemblies and Beyond Peter Bai, Sui Yang, Wei Bao, Miquel Salmeron, Xiang Zhang, Ting Xu Block copolymer-based supramolecules provide a versatile platform to direct the self-assembly of nanoparticles (NPs) into precisely controlled nanostructures in bulk and thin film geometries. A supramolecule, PS-b-P4VP(PDP), composed of the small molecule 3-pentadecylphenol (PDP) hydrogen bonded to a diblock copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), was subjected to 2-D volume confinement in cylindrical anodic aluminum oxide (AAO) membrane pores. TEM and 3-D TEM tomography reveal that the morphologies accessible by the supramolecule and supramolecule/NP composites, such as NP clusters, arrays, stacked rings, and single and double helical ribbons, are significantly different from those in the bulk or thin film. Furthermore, single molecule dark field scattering measurements demonstrate strong chiral optical response of single helical Au NP ribbon nanostructures in the near infrared wavelength regime. These studies demonstrate 2-D confinement to be an effective means to tailor self-assembled NP structure within supramolecule nanocomposites and pave the way for this assembly approach to be applied towards next generation chiral metamaterials and optoelectronic devices. [Preview Abstract] |
Wednesday, March 4, 2015 4:18PM - 4:54PM |
Q39.00010: Harnessing Biomimetic Catch Bonds to Create Mechanically Robust Nanoparticle Networks Invited Speaker: Anna Balazs Using computer simulations, we investigate the mechanical properties of a network of polymer-grafted nanoparticles (PGNs) that are interlinked by labile ``catch'' bonds. In contrast to conventional ``slip'' bonds, the life time of catch bonds can potentially increase with the application of force (i.e., the rate of rupture can decrease). In effect, the bond becomes stronger under an applied force (if the strain rate is sufficiently high). Subjecting the PGN networks to a tensile deformation, we find that the networks encompassing catch bonds exhibit greater ductility and toughness than the networks interconnected by slip bonds. Moreover, when the applied tensile force is released, the catch bond networks exhibit lower hysteresis and faster relaxation of residual strain than the slip bond networks. The effects of the catch bonds on the mechanical behavior are attributed to transitions between two conformational states, which differ in their sensitivity to force. The findings provide guidelines for creating nanocomposite networks that are highly resistant to mechanical deformation and show rapid strain recovery. [Preview Abstract] |
Wednesday, March 4, 2015 4:54PM - 5:06PM |
Q39.00011: Microwave Induced Welding of Carbon Nanotube-Thermoplastic Interfaces for Enhanced Mechanical Strength of 3D Printed Parts Charles Sweeney, Micah Green, Mohammad Saed Three-dimensional (3D) printed parts produced by fused-filament fabrication of a thermoplastic polymer have become increasingly popular at both the commercial and consumer level. The mechanical integrity of these rapid-prototyped parts however, is severely limited by the interfillament bond strength between adjacent extruded layers. In this report we propose for the first time a method for welding thermoplastic interfaces of 3D printed parts using the extreme heating response of carbon nanotubes (CNTs) to microwave energy. To achieve this, we developed a coaxial printer filament with a pure polylactide (PLA) core and a CNT composite sheath. This produces parts with a thin electrically percolating network of CNTs at the interfaces between adjacent extruded layers. These interfaces are then welded together upon microwave irradiation at 2.45GHz. We investigated the dielectric properties of the PLA/CNT composites at microwave frequencies and performed in-situ microwave thermometry using a forward-looking infrared (FLIR) camera to characterize the heating response of the PLA/CNT composites upon microwave irradiation. Finally, computational models were developed to verify the microwave heating response of the percolating CNT composites according to their measured dielectric properties. [Preview Abstract] |
Wednesday, March 4, 2015 5:06PM - 5:18PM |
Q39.00012: Smart Hybrids made of Polymer Brushes and Gold Nanospheres Stephanie Christau, Felix Brose, Tim Moeller, Ralf Koehler, Zuleyha Yenice, Jan Genzer, Regine von Klitzing The modification of surfaces by coating with polymer brushes has attracted much interest in the past few years due to numerous potential applications in material and life science for the development of smart surfaces. They can be used as 3D matrices for the immobilization of nanoparticles, resulting in nanocomposite materials with interesting mechanical, optical, or catalytic properties with tailored functions [1]. Studying the mutual influence of the brush matrix and the attached AuNPs on the structure of the resulting brush/AuNP hybrid will allow fine-tuning of the particle loading and distribution . this study, responsive poly-(N,N-dimethylamino)ethyl methacrylate (PDMAEMA) and poly-(N-isopropylacrylamide) (PNIPAM) brushes are used as a matrix for the attachment of spherical gold nanoparticles (AuNPs). We find that the uptake and distribution of nanoparticles in polymer brush matrices depends greatly on the brush thickness [2], brush grafting density [3], polymer chemistry, particle surface functionalization and particle size. References: [1] S. Christau et al. \textit{Z. Phys. Chem}., 2014 [2] S. Christau et al. \textit{Polymers}, 2014, 6, 1877. [3] S. Christau et al. \textit{Langmuir}, 2014, 30, 13033 [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700