Bartosz A Grzybowski

Northwestern University, Evanston, Illinois, United States

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Publications (208)1939.52 Total impact

  • Bilge Baytekin, H. Tarik Baytekin, Bartosz A. Grzybowski
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    ABSTRACT: Mechanical treatment of polymers produces surface cations and anions which, as demonstrated here for the first time, can drive chemical reactions. In particular, it is shown that such a mechanical treatment transforms nonconductive polyaniline into its conductive form. These results provide a mechanical means of patterning conductive polymers and also coating small polymer objects with conductive polyaniline films preventing accumulation of static electricity.
    Angewandte Chemie 05/2014;
  • Bilge Baytekin, H. Tarik Baytekin, Bartosz A. Grzybowski
    [Show abstract] [Hide abstract]
    ABSTRACT: Mechanical treatment of polymers produces surface cations and anions which, as demonstrated here for the first time, can drive chemical reactions. In particular, it is shown that such a mechanical treatment transforms nonconductive polyaniline into its conductive form. These results provide a mechanical means of patterning conductive polymers and also coating small polymer objects with conductive polyaniline films preventing accumulation of static electricity.
    Angewandte Chemie International Edition 05/2014; · 13.73 Impact Factor
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    ABSTRACT: In materials design, cracks are often avoided rather than sought. Here, several design principles are implemented that allow cracks to be formed with high reproducibility and control. We show how strains applied to flexible substrates produce nanoscopic cracks mediating size-, shape- and location-selective deposition of nanomaterials.
    Advanced Materials 04/2014; · 14.83 Impact Factor
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    ABSTRACT: When mammalian cells form confluent monolayers completely filling a plane, these apparently random "tilings" show regularity in the statistics of cell areas for various types of epithelial and endothelial cells. The observed distributions are reproduced by a model which accounts for cell growth and division, with the latter treated stochastically both in terms of the sizes of the dividing cells as well as the sizes of the "newborn" ones-remarkably, the modeled and experimental distributions fit well when all free parameters are estimated directly from experiments.
    Physical Review Letters 04/2014; 112(13):138104. · 7.94 Impact Factor
  • Seok Min Yoon, Scott C. Warren, Bartosz A. Grzybowski
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    ABSTRACT: Single crystals of a cyclodextrin-based metal–organic framework (MOF) infused with an ionic electrolyte and flanked by silver electrodes act as memristors. They can be electrically switched between low and high conductivity states that persist even in the absence of an applied voltage. In this way, these small blocks of nanoporous sugar function as a non-volatile RRAM memory elements that can be repeatedly read, erased, and re-written. These properties derive from ionic current within the MOF and the deposition of nanometer-thin passivating layers at the anode flanking the MOF crystal. The observed phenomena are crucially dependent on the sub-nanometer widths of the channels in the MOF, allowing the passage of only smaller ions. Conversely, with the electrolyte present but no MOF, there are no memristance or memory effects.
    Angewandte Chemie 03/2014;
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    ABSTRACT: Gold nanoparticles (NPs) functionalized with 2-fluoro-4-mercaptophenol (FMP) ligands form densely packed NP films at liquid-liquid interfaces, including surfaces of liquid droplets. The process is driven by a gradual lowering of temperature that changes the solution's pH, altering both the energy of interfacial adsorption for NPs traveling from solution to the interface as well as the balance between electrostatic and vdW interactions between these particles. Remarkably, the system shows hysteresis in the sense that the films remain stable when the temperature is increased back to the initial value. The same phenomena apply to gel-air interfaces, enabling patterning of these wet materials with durable NP films.
    Nanoscale 01/2014; · 6.23 Impact Factor
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    ABSTRACT: Self-replication is a remarkable phenomenon in nature that has fascinated scientists for decades. In a self-replicating system, the original units are attracted to a template, which induce their binding. In equilibrium, the energy required to disassemble the newly assembled copy from the mother template is supplied by thermal energy. The possibility of optimizing self-replication was explored by controlling the frequency at which energy is supplied to the system. A model system inspired by a class of light-switchable colloids was considered where light is used to control the interactions. Conditions under which self-replication can be significantly more effective under non-equilibrium, cyclic energy delivery than under equilibrium constant energy conditions were identified. Optimal self-replication does not require constant energy expenditure. Instead, the proper timing at which energy is delivered to the system is an essential controllable parameter to induce high replication rates.
    Angewandte Chemie International Edition 11/2013; · 13.73 Impact Factor
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    ABSTRACT: Interest in assemblies of colloidal particles has long been motivated by their applications in photonics, electronics, sensors and microlenses. Existing assembly schemes can position colloids of one type relatively flexibly into a range of desired structures, but it remains challenging to produce multicomponent lattices, clusters with precisely controlled symmetries and three-dimensional assemblies. A few schemes can efficiently produce complex colloidal structures, but they require system-specific procedures. Here we show that magnetic field microgradients established in a paramagnetic fluid can serve as 'virtual moulds' to act as templates for the assembly of large numbers (∼10(8)) of both non-magnetic and magnetic colloidal particles with micrometre precision and typical yields of 80 to 90 per cent. We illustrate the versatility of this approach by producing single-component and multicomponent colloidal arrays, complex three-dimensional structures and a variety of colloidal molecules from polymeric particles, silica particles and live bacteria and by showing that all of these structures can be made permanent. In addition, although our magnetic moulds currently resemble optical traps in that they are limited to the manipulation of micrometre-sized objects, they are massively parallel and can manipulate non-magnetic and magnetic objects simultaneously in two and three dimensions.
    Nature 10/2013; · 38.60 Impact Factor
  • Source
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    ABSTRACT: Metastatic breast cancer cells move not only more rapidly and persistently than their non-metastatic variants but in doing so use the mechanical work of the cytoskeleton more efficiently. The efficiency of the cell motions is defined for entire cells (rather than parts of the cell membrane) and is related to the work expended in forming membrane protrusions and retractions. This work, in turn, is estimated by integrating the protruded and retracted areas along the entire cell perimeter and is standardized with respect to the net translocation of the cell. A combination of cross-correlation, Granger causality, and morphodynamic profiling analyses is then used to relate the efficiency to the cell membrane dynamics. In metastatic cells, the protrusions and retractions are highly "synchronized" both in space and in time and these cells move efficiently. In contrast, protrusions and retractions formed by non-metastatic cells are not "synchronized" corresponding to low motility efficiencies. Our work provides a link between the kinematics of cell motions and their energetics. It also suggests that spatiotemporal synchronization might be one of the hallmarks of invasiveness of cancerous cells.
    Integrative Biology 10/2013; · 4.32 Impact Factor
  • Jason R Green, Anthony B Costa, Bartosz A Grzybowski, Igal Szleifer
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    ABSTRACT: Connections between microscopic dynamical observables and macroscopic nonequilibrium (NE) properties have been pursued in statistical physics since Boltzmann, Gibbs, and Maxwell. The simulations we describe here establish a relationship between the Kolmogorov-Sinai entropy and the energy dissipated as heat from a NE system to its environment. First, we show that the Kolmogorov-Sinai or dynamical entropy can be separated into system and bath components and that the entropy of the system $${h}_{sys}$$ characterizes the dynamics of energy dissipation. Second, we find that the average change in the system dynamical entropy is linearly related to the average change in the energy dissipated to the bath. The constant energy and time scales of the bath fix the dynamical relationship between these two quantities. These results provide a link between microscopic dynamical variables and the macroscopic energetics of NE processes.
    Proceedings of the National Academy of Sciences 09/2013; · 9.74 Impact Factor
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    ABSTRACT: Even minute quantities of electric charge accumulating on polymer surfaces can cause shocks, explosions, and multibillion-dollar losses to electronic circuitry. This paper demonstrates that to remove static electricity, it is not at all necessary to "target" the charges themselves. Instead, the way to discharge a polymer is to remove radicals from its surface. These radicals colocalize with and stabilize the charges; when they are scavenged, the surfaces discharge rapidly. This radical-charge interplay allows for controlling static electricity by doping common polymers with small amounts of radical-scavenging molecules, including the familiar vitamin E. The effectiveness of this approach is demonstrated by rendering common polymers dust-mitigating and also by using them as coatings that prevent the failure of electronic circuitry.
    Science 09/2013; 341(6152):1368-71. · 31.20 Impact Factor
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    ABSTRACT: When organic molecules are tethered onto non-spherical nanoparticles, their chemical properties depend on the particles' local curvature and shape. Based on this observation, we show here that it is possible to engineer chemical patchiness across the surface of a non-spherical nanoparticle using a single chemical species. In particular, when acidic ligands are used, regions of the particle surface with different curvature become charged at different pH values of the surrounding solution. This interplay between particle shape and local electrostatics allows for fine control over nanoscale self-assembly leading to structures with varying degrees of complexity. These structures range from particle cross-stacks to open-lattice crystals, the latter with pore sizes on the order of tens of nanometres, that is, at the lower synthetic limits of metallic mesoporous materials.
    Nature Nanotechnology 08/2013; · 31.17 Impact Factor
  • Konstantin V Tretiakov, Igal Szleifer, Bartosz A Grzybowski
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    ABSTRACT: Outside thermodynamic equilibrium, outcomes of self-assembly can be dictated not by energy but by the energy dissipation rate. Remarkably, non-equilibrium self-assembly can lead to both low- and high-dissipation structures. The latter, thermodynamically more wasteful structures are exponentially less probable with increasing dissipation rate. This dependence is quantified in a Boltzmann-like relation for non-equilibrium systems.
    Angewandte Chemie International Edition 07/2013; · 13.73 Impact Factor
  • Shuangbing Han, Yanhu Wei, Bartosz A Grzybowski
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    ABSTRACT: Occlusion and confinement of a [Ru(bpy)3 ]Cl2 photocatalyst in the cavities of a γ-cyclodextrin (CD) metal-organic framework (MOF) does not affect the catalyst's activity but prevents its photodegradation. Additionally, the OH(-) ions and/or ROH groups present inside the CD-MOF act as electron donors and complete the catalytic cycle. The occlusion approach is a technically straightforward alternative to the covalent modification of MOF scaffolds with catalytic units.
    Chemistry 07/2013; · 5.93 Impact Factor
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    ABSTRACT: Complex behavior in glassforming liquids is associated with formation of a mosaic of different structures. Using bond order parameters together with topological characteristics of the bond network, we show that in the mosaic of crystalline and amorphous clusters found in a 2D liquid the difference between structural sub- components translates into a difference between two coexisting phases. We suggest that the observed microphase separated mosaic is a 2D realization of what is usually invoked to explain special features found in 3D complex liquids. Conditions favoring mosaic stability are discussed; these conditions include a new type of critical behavior and long-range correlations between sub-component clusters.
  • Source
    Kyle J M Bishop, Nicolas R Chevalier, Bartosz A Grzybowski
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    ABSTRACT: Like-sized, oppositely charged nanoparticles are known to assemble into large crystals with diamond-like (ZnS) ordering, in sharp contrast to analogous molecular ions and micrometer-scale colloids, which invariably favor more closely packed structures (NaCl or CsCl). Here, we show that these experimental observations can be understood as a consequence of ionic screening and the slight asymmetry in surface charge present on the assembling particles. With this asymmetry taken into account, free-energy calculations predict that the diamond-like ZnS lattice is more favorable than other 1:1 ionic structures, namely, NaCl or CsCl, when the Debye screening length is considerably larger than the particle size. A thermodynamic model describes how the presence of neutralizing counterions within the interstitial regions of the crystal acts to bias the formation of low-volume-fraction structures. The results provide general insights into the self-assembly of non-close-packed structures via electrostatic interactions.
    Journal of Physical Chemistry Letters 04/2013; · 6.59 Impact Factor
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    ABSTRACT: Nanoparticles functionalized with mixed self-assembled monolayers (m-SAMs) comprising positively-and negatively charged thiols are stable in both low and high pH but precipitate sharply at pHprec at which the charges on the particle are balanced. By adjusting the proportion of the (+) and the (-) ligands in the m-SAM, or by changing particle size, the precipitation point can be varied flexibly between pH ~ 4 and pH ~ 7. In addition, changes in the SAMs' com-position and particles' net charge translate into different degrees of cellular uptake. Remarkably, the presence of the (+) thiols allows for the uptake of particles having net nega-tive charge.
    Journal of the American Chemical Society 03/2013; · 10.68 Impact Factor
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    ABSTRACT: Physical–chemical reasoning is used to demonstrate that the sizes of both prokaryotic and eukaryotic cells are such that they minimize the times needed for the macromolecules to migrate throughout the cells and interact/react with one another. This conclusion does not depend on a particular form of the crowded-medium diffusion model, as thus points toward a potential optimization principle of cellular organisms. In eukaryotes, size optimality renders the diffusive transport as efficient as active transport – in this way, the cells can conserve energetic resources that would otherwise be expended in active transport.
    Journal of Physical Chemistry Letters 03/2013; 4(6):861–865. · 6.59 Impact Factor
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    ABSTRACT: Regular arrays of nanorods having asymmetric cross-sections are fabricated by a combination of electrodeposition and glancing-angle deposition (GLAD). When these nanorods are embedded in a polymer matrix, they give rise to composite materials in which the structural anisotropy at the nanoscale translates into functional anisotropy in the form of direction-dependent electrical bistability. The degree of this directional bistability depends on and can be controlled by the spacing between the nearby nanorods.
    Advanced Materials 01/2013; · 14.83 Impact Factor
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    ABSTRACT: Donor-acceptor [4]- and [6]rotaxanes have been prepared from bipyridinium (BIPY(2+)) oligomers and 1,5-dinaphtho[38]crown-10 (DN38C10) by a threading-followed-by-stoppering protocol employing click chemistry. An efficient, straightforward route to the BIPY(2+) oligomers has been developed that requires little to no chromatographic purification. Unlike most donor-acceptor oligorotaxanes that have been reported to date, 100% of the recognition sites on the dumbbells are occupied by rings.
    Organic Letters 09/2012; 14(19):5066-9. · 6.14 Impact Factor

Publication Stats

4k Citations
1,939.52 Total Impact Points


  • 2004–2014
    • Northwestern University
      • • Department of Chemical and Biological Engineering
      • • Department of Chemistry
      Evanston, Illinois, United States
  • 2013
    • Polish Academy of Sciences
      • Institute of Molecular Physics
      Warsaw, Masovian Voivodeship, Poland
  • 2012
    • Pennsylvania State University
      • Department of Chemical Engineering
      University Park, MD, United States
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States
  • 2011
    • Northwestern Polytechnical University
      • School of Materials Science and Engineering
      Xi’an, Liaoning, China
  • 2005
    • New England Complex Systems Institute
      Evanston, Illinois, United States
  • 1999–2003
    • Harvard University
      • Department of Chemistry and Chemical Biology
      Cambridge, MA, United States