George M. Whitesides

Bio: George M. Whitesides is an academic researcher from Harvard University. The author has contributed to research in topics: Microcontact printing & Self-assembled monolayer. The author has an hindex of 240, co-authored 1739 publications receiving 269833 citations. Previous affiliations of George M. Whitesides include University of California, Davis & University of Texas at Austin.

Coding/Decoding and Reversibility of Droplet Trains in Microfluidic Networks

Abstract: Droplets of one liquid suspended in a second, immiscible liquid move through a microfluidic device in which a channel splits into two branches that reconnect downstream. The droplets choose a path based on the number of droplets that occupy each branch. The interaction among droplets in the channels results in complex sequences of path selection. The linearity of the flow through the microchannels, however, ensures that the behavior of the system can be reversed. This reversibility makes it possible to encrypt and decrypt signals coded in the intervals between droplets. The encoding/decoding device is a functional microfluidic system that requires droplets to navigate a network in a precise manner without the use of valves, switches, or other means of external control.

Buckling Pneumatic Linear Actuators Inspired by Muscle

Abstract: Dr. D. Yang, Dr. M. S. Verma, Dr. J.-H. So, Prof. B. Mosadegh, Prof. C. Keplinger, B. Lee, F. Khashai, E. Lossner, Prof. G. M. Whitesides Department of Chemistry and Chemical Biology Harvard University 12 Oxford Street , Cambridge , MA 02138 , USA E-mail: gwhitesides@gmwgroup.harvard.edu Dr. D. Yang, Prof. Z. Suo School of Engineering and Applied Sciences Harvard University 29 Oxford Street , Cambridge , MA 02138 , USA Prof. B. Mosadegh, Prof. G. M. Whitesides Wyss Institute for Biologically Inspired Engineering Harvard University 60 Oxford Street , Cambridge , MA 02138 , USA Prof. Z. Suo, Prof. G. M. Whitesides Kavli Institute for Bionano Science & Technology Harvard University 29 Oxford Street , Cambridge , MA 02138 , USA

Molecular self-assembly through hydrogen bonding : supramolecular aggregates based on the cyanuric acid.melamine lattice

Abstract: Reaction of the tris(melamine) derivatives hubMr (CnHr- 1,3,5-(CONHC6H4- 3-N(9ryrCnHo-4-C (CHr)r)COC6- H,-2-NHC.,Nr(NHr )(NHCHTCHTC(CHr) r)-5-Brl.) and flexM. (CoHr-1,3,5 (CO:(CHr),OCOC6H I-2-NHCTN)(NH2)( N- HCHTCHT(CU,lrltJ with R,CA (neohexyl isocyanuiate) and R"CA (3,3,3-triphenylpropyt isocy-anurate) in CHClr, respectively, yields ,truiturali.r- well-defined supramoleculir aggregates hubMq(R'CA)3 and flexM3(R"CA)3. These structures were characterized using ,H NMR, rlC NMR, and UV spectroscopy, gel permeation chromatography, and vapor pressure osmometry. flexM, is a confor-mationally flexible analog of hubM.,. The greater degree of preorganization that is built into the molecular structure of hubM3 compaied to flexM., ttiuk.r hubMr(R'Cn)i a more stable aggregate than flexMr(R"CA)r. These self- assembling structuies arethe first step in a program to design, synthesize. and develop methods to characterize supramolecular

Imaging of features on surfaces by condensation figures

Abstract: Condensation of a vapor to a liquid on a cold surface that is not wet completely by this liquid leads to the formation of an array of droplets. If the surface is heterogeneous in its physical properties (especially its interfacial free energy), the patterns of these arrays reflect this heterogeneity. The distribution of droplets of water (condensation figures or CFs) observed by optical microscopy on a surface can be correlated with the molecular structure of that surface. The substrates used to investigate the formation and morphology of the CFs were patterned, self-assembled monolayers of different alkanethiolates on gold and of alkyl siloxanes on glass. Analysis of CFs is a valuable nondestructive technique for characterizing heterogeneities in surfaces.

Selective Deposition of Conducting Polymers on Hydroxyl-Terminated Surfaces with Printed Monolayers of Alkylsiloxanes as Templates

Abstract: This paper describes the use of patterned self-assembled monolayers (SAMs) in area-selective deposition of conducting polymers (polypyrrole and polyaniline) on insulating, hydroxyl-terminated surfaces such as Si/SiO2 and glass. Patterned SAMs of octadecylsiloxane were generated on the hydroxyl-terminated surfaces using microcontact printing; they defined and directed the deposition of conducting polymers. The rate of deposition on the hydrophobic surface is higher than that on the hydrophilic surface: immersion of a substrate patterned with a methyl-terminated SAM in an appropriate aqueous polymerization bath produced a “positive” pattern of the conducting polymer on the surface. The conducting polymer deposited on the hydrophobic region of a surface completely covered by the polymer could be readily removed by transferring it to adhesive tape to form a “positive” pattern on the tape, leaving a “negative” pattern on the surface of the substrate. The conducting polymer deposited on the hydrophobic surface...

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Large-scale pattern growth of graphene films for stretchable transparent electrodes

Abstract: Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

Fuzzy Nanoassemblies: Toward Layered Polymeric Multicomposites

Abstract: Multilayer films of organic compounds on solid surfaces have been studied for more than 60 years because they allow fabrication of multicomposite molecular assemblies of tailored architecture. However, both the Langmuir-Blodgett technique and chemisorption from solution can be used only with certain classes of molecules. An alternative approach—fabrication of multilayers by consecutive adsorption of polyanions and polycations—is far more general and has been extended to other materials such as proteins or colloids. Because polymers are typically flexible molecules, the resulting superlattice architectures are somewhat fuzzy structures, but the absence of crystallinity in these films is expected to be beneficial for many potential applications.