From dynamic self-assembly to networked chemical systems

Grzybowski, Bartosz A.,Fitzner, Krzysztof,Paczesny, Jan,Granick, Steve The Royal Society of Chemistry 2017 Chemical Society reviews Vol.46 No.18

<P>Although dynamic self-assembly, DySA, is a relatively new area of research, the past decade has brought numerous demonstrations of how various types of components - on scales from (macro)molecular to macroscopic - can be arranged into ordered structures thriving in non-equilibrium, steady states. At the same time, none of these dynamic assemblies has so far proven practically relevant, prompting questions about the field's prospects and ultimate objectives. The main thesis of this Review is that formation of dynamic assemblies cannot be an end in itself - instead, we should think more ambitiously of using such assemblies as control elements (reconfigurable catalysts, nanomachines,<I>etc.</I>) of larger, networked systems directing sequences of chemical reactions or assembly tasks. Such networked systems would be inspired by biology but intended to operate in environments and conditions incompatible with living matter (<I>e.g.</I>, in organic solvents, elevated temperatures,<I>etc.</I>). To realize this vision, we need to start considering not only the interactions mediating dynamic self-assembly of individual components, but also how components of different types could coexist and communicate within larger, multicomponent ensembles. Along these lines, the review starts with the discussion of the conceptual foundations of self-assembly in equilibrium and non-equilibrium regimes. It discusses key examples of interactions and phenomena that can provide the basis for various DySA modalities (<I>e.g.</I>, those driven by light, magnetic fields, flows,<I>etc.</I>). It then focuses on the recent examples where organization of components in steady states is coupled to other processes taking place in the system (catalysis, formation of dynamic supramolecular materials, control of chirality,<I>etc.</I>). With these examples of functional DySA, we then look forward and consider conditions that must be fulfilled to allow components of multiple types to coexist, function, and communicate with one another within the networked DySA systems of the future. As the closing examples show, such systems are already appearing heralding new opportunities - and, to be sure, new challenges - for DySA research.</P>

The nanotechnology of life-inspired systems

Grzybowski, Bartosz A.,Huck, Wilhelm T. S. Nature Publishing Group, a division of Macmillan P 2016 Nature nanotechnology Vol.11 No.7

<p>For some decades now, nanotechnology has been touted as the 'next big thing' with potential impact comparable to the steam, electricity or Internet revolutions — but has it lived up to these expectations? While advances in top-down nanolithography, now reaching 10-nm resolution, have resulted in devices that are rapidly approaching mass production, attempts to produce nanoscale devices using bottom-up approaches have met with only limited success. We have been inundated with nanoparticles of almost any shape, material and composition, but their societal impact has been far from revolutionary, with growing concerns over their toxicity. Despite nebulous hopes that making hierarchical nanomaterials will lead to new, emergent properties, no breakthrough applications seem imminent. In this Perspective, we argue that the time is ripe to look beyond individual nano-objects and their static assemblies, and instead focus on systems comprising different types of 'nanoparts' interacting and/or communicating with one another to perform desired functions. Such systems are interesting for a variety of reasons: they can act autonomously without external electrical or optical connections, can be dynamic and reconfigurable, and can act as 'nanomachines' by directing the flow of mass, energy or information . In thinking how this systems nanoscience approach could be implemented to design useful — as opposed to toy-model — nanosystems, our choice of applications and our nanoengineering should be inspired by living matter.</p>

Terrestrial humic substances induce photodegradation of polysaccharides in the aquatic environment

Grzybowski, Waldemar Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.10

Starch solution (4 mg $dm^{-3}$) was irradiated with simulated solar UV radiation with and without addition of Aldrich humic acids (8 mg $dm^{-3}$). Quantitative analysis of the photodegradation products revealed enhanced release of monosaccharides in the presence of humic substances.

Solvatofluorochromic, non-centrosymmetric π-expanded diketopyrrolopyrrole

Grzybowski, Marek,Jeż,ewski, Artur,Deperasiń,ska, Irena,Friese, Daniel H.,Banasiewicz, Marzena,Hugues, Vincent,Kozankiewicz, Bolesław,Blanchard-Desce, Mireille,Gryko, Daniel T. The Royal Society of Chemistry 2016 Organic & Biomolecular Chemistry Vol.14 No.6

<P>A novel non-centrosymmetric π-expanded diketopyrrolopyrrole was designed and synthesized. Strategic placement of <I>tert</I>-butyl groups at the periphery of a diketopyrrolopyrrole allowed us to selectively fuse one moiety <I>via</I> tandem Friedel–Crafts-dehydration reactions, resulting in a non-centrosymmetric dye. The structure of the dye was confirmed by X-ray crystallography, revealing that it contains a nearly flat arrangement of four fused rings. Extensive photophysical studies of this new functional dye revealed that the intensity of its emission strongly depends on solvent polarity, which is typical for dipolar chromophores. In non-polar solvents, the fluorescence quantum yield is high whereas in polar solvents such as MeOH, it is 12%. However, upon two-photon excitation the compound behaves like a centrosymmetric dye, showing a two-photon absorption maximum at significantly shorter wavelengths than twice the wavelength of the one-photon absorption maximum.</P> <P>Graphic Abstract</P><P>A donor–acceptor type π-expanded diketopyrrolopyrrole behaves as non-centrosymmetric as far as linear optical properties are concerned but as ‘pseudo-symmetric’ for two-photon absorption. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5ob02583d'> </P>

Multistress Life Models of Epoxy Encapsulated Magnet wire under High Frequency Pulsating Voltage

Grzybowski, S.,Feilat, E.A.,Knight, P. The Korean Institute of Electrical Engineers 2003 KIEE International Transactions on Electrophysics Vol.3C No.1

This paper presents an attempt to develop probabilistic multistress life models to evaluate the lifetime characteristics of epoxy-encapsulated magnet wire with heavy build polyurethane enamel. A set of accelerated life tests were conducted over a wide range of pulsating voltages, temperatures, and frequencies. Samples of fine gauge twisted pairs of the encapsulated magnet wire were tested us-ing a pulse endurance dielectric test system. An electrical-thermal lifetime function was combined with the Weibull distribution of lifetimes. The parameters of the combined Weibull-electrical-thermal model were estimated using maximum likelihood estimation. Likewise, a generalized electrical-thermal-frequency life model was also developed. The parameters of this new model were estimated using multiple linear regression technique. It was found in this paper that lifetime estimates of the two proposed probabilistic multistress life models are good enough. This suggests the suitability of using the general electrical-thermal-frequency model to estimate the lifetime of the encapsulated magnet wire over a wide range of voltages, temperatures and pulsating frequencies.

Electrical Breakdown Strength of Insulation under Combined DC-AC Voltages

Grzybowski, S. The Korean Institute of Electrical and Electronic 1998 전기전자재료 Vol.11 No.10

Electrical breakdown strength of paper-oil and polypropylene/film-oil insulation samples was measured under dc, ac and pulsating voltages. The latter was obtained by superimposing ac upon dc volate and provides an attractive method for a simultaneous testing and assessment of the state of insulation of the various parts of HV apparatus in service. The measurements were carried out over a wide range of the pulsation ratio defined as p=Eac/Edc. The results obtained under pulsating voltages follow colsely an experssion which relates the breakdown strength to the sum of arc tangent and arc cotangent function of the parameter p. The study was carried out using dry paper as well as paper containing various degrees of moisture. The presence of moisture showed a pronounced effect upon the breakdown strength which varied with the pulsation parameter p.

Multistress Life Models of Epoxy Encapsulated Magnet Wire under High Frequency Pulsating Voltage

S. Grzybowski,E. A. Feilat,P. Knight 대한전기학회 2003 KIEE International Transactions on Electrophysics Vol.3C No.1

Self-assembly, trapping and manipulation of nonmagnetic microobjects with magnetic fields

Bartosz A. Grzybowski 한국고분자학회 2015 한국고분자학회 학술대회 연구논문 초록집 Vol.2015 No.10

Theoretical basis for the stabilization of charges by radicals on electrified polymers

Mazur, T.,Grzybowski, B. THE ROYAL SOCIETY OF CHEMISTRY 2017 Chemical Science Vol.8 No.3

<P>Quantum mechanical calculations at various levels of theory indicate that charges (both '+' and '-') on organic polymers can be stabilized by radicals on nearby polymer chains. The stabilization mechanism is based on the formation of intermolecular odd-electron, two-center bonds with possible concomitant spin density redistribution (depending on the polymer and the number and type of proximal heteroatoms). This result is in line with our previous experimental demonstrations that on various types of polymers charged by contact electrification, radicals co-localize and help stabilize proximal charges (of either polarity). The principle of intramolecular charge-radical stabilization we now confirm on a fundamental level might have ramifications for the design of other macromolecular systems in which chemical reactivity is controlled by radicals flanking the charged groups or by charged groups flanking the radicals.</P>

Active colloids with collective mobility status and research opportunities

Zhang, J.,Luijten, E.,Grzybowski, B.,Granick, S. Royal Society of Chemistry 2017 Chemical Society reviews Vol.46 No.18