Gecko Know–How!

The fabrication of hairy films, inspiredby the keratinous hairs found on thesoles ofGecko feet, is describedbyWooK. Cho and Insung S. Choi in a paperpublished in Advanced FunctionalMaterials this month. Such hairsafford the Gecko the ability to stick toand climb upmany different surfaces.

In this work, a facile, efficient replica-molding technique is used to form thefilms, which demonstrate very strongadhesion properties coupled with avery high contact angle that leads tosuperhydrophobicity. /lms

I. S. Choi et al., Adv. Funct. Mater. 2008, 18,1089

Polymer-ProteinBioconjugates by RAFTand Click Chemistry

Modification of biomacromoleculeswith synthetic polymers is a viablemeans to increase efficacy for in vivoand in vitro applications. Bioconju-gates with stimuli-susceptibility areparticularly interesting because of theability of the attached polymer toimpart responsiveness to the proteinto which it is attached. Recently

Sumerlin et al. have reported a novelsynthesis route of responsive poly-mer-protein conjugates by a combina-tion of RAFT polymerization and clickchemistry. A model protein, bovineserum albumin (BSA), was functional-ized with an alkyne moiety by reac-tion of its free cysteine residue withpropargyl maleimide. Azido-termi-nated poly(N-isopropylacrylamide)(PNIPAM-N3) was prepared via RAFT,and polymer-protein coupling wasaccomplished by copper-catalyzedazide-alkyne cycloaddition. /ct

B. S. Sumerlin et al., Macromol. RapidCommun., DOI: 10.1002/marc.200800073

Precious Acoustics

Among itsmany exceptional qualities,themechanical properties of diamondmake the material especially interest-ing for acoustic applications. Whileelectronic device development is stillstruggling with large-area substrategrowth and the intricate art of dia-mond doping, surface acoustic wavefilters based on diamond have reachedthe market. The appealing combina-tion of diamond’s bio-inertness withthe high sensitivity of acoustic sensorsmotivates the ongoing search forimprovement and alternative deviceconcepts. In their Feature Article, theauthors summarize the state-of-the-art of diamond films in compositeacoustic applications and review dif-ferent types of acoustic devices andsensors. /sb

V. Mortet et al., phys. status solidi a, DOI10.1002/pssa.200777502

In BriefSuper-Tough NanocompositesAdramatic increase in the toughness (elongationbefore failure from 7% to 210%) of the bio-compatible and biodegradable poly(lactide-co-glycolide) is achieved by the addition of smallamounts of surface modified clay nanoparticles,which introduce physical crosslinks. /ks

E. P. Giannelis et al., Small, DOI: 10.1002/

smll.200701231

Transparent 8Y CeramicsThe high transparency of Y2O3–ZrO2 (8Y) ceramicsproduced by the hot isotactic pressing method issensitive to the microstructural features of finegrains and small intergranular pores of the pre-sintered material, with a porosity less than100 ppm required for high transparency. /df

I. Yamashita et al., J. Am. Ceram. Soc. 2008, 91,

813.

Green Polymer ChemistryCommercial available PEGs canbe quantitativelyfunctionalized to a-o telechelic PEG-methacrylatesand PEG-acetates by transesterification usingCandida antarctica lipase B (Novozyme 435) asthe catalyst. /ct

J. E. Puskas et al. J. Polym. Sci. A: Polym. Chem.,

DOI: 10.1002/pola.22640

Alloy Rain: Watching FallingDroplets SolidifyFree falling and electromagnetically levitatedalloy droplets allow direct measurement ofundercooling and crystallization front velocitytowards microstructure engineering from themelt. /mo

D. M. Herlach et al., Adv. Eng. Mater., DOI:

10.1002/adem.200800022

Hydrogenation ofPoly(phenylethylnorbornene)sHydrogenation of norbornene polymers, used inelectronics applications, produces two differentderivatives, with the phenyl groups either pre-served or saturated, that exhibit very differentglass-transition properties. /gk

R. A. Register et al., Macromol. Rapid Commun.,

DOI: 10.1002/marc.200800019

Editor: Sandra Kalveram (sk)Contributors: S. Bahrs (sb), D. Flanagan (df),S. Hildebrandt (sh), G. Kemeling (gk),K. Madefessel-Herrmann (kmh),M. Ottmar (mo), A. Pichon (ap), K. Severing (ks),L. Stimson (lms), C. Teutsch (ct)E-mail: materialsviews@wiley-vch.dewww.materialsviews.com

Materials Views 2008, June, A1–A8 � 2008 John Wiley & Sons, Inc. A1

A Facile Way to ColloidPhotonic Crystals

Amajor obstacle to the practical use ofcolloidal crystals is a lackof simple andreliable methods for consolidating thecolloidal particles into crystals withwell controlled shapes, sizes, andstructures over fast time scales. S.-M.Yang et al. report a novel and simplemethod for creating various structuralmotifs of colloidal crystals by usingsilica particles dispersed in ethoxy-lated trimethylolpropane triacrylate(ETPTA)resinandphotoinducedconso-lidation. Various colloidal suprastruc-tures can be fabricated in that way.

The strong polarity of the ETPTA ma-trix induces long-range repulsions andenables the silica particles to self-assem-ble into periodic non-close-packedstructures dispersed in the matrix.These self-organized structures canthen be rapidly solidified by UV expo-sure to produce colloidal crystalswithout cracks. The high chemicalresistivity and physical rigidity ofcrosslinked ETPTA open a wide rangeof applications. /ks

S.-M. Yang et al., Adv. Mater., DOI: 10.1002/adma.200703022

Silver Bullet SlaysBacteria!

Self-sterilizing surfaces that automa-tically release antimicrobial silvernanoparticles in the presence ofmicro-organisms have recently beendemonstrated by Wendelin Stark andhis co-workers. Their paper, publishedin Small thismonth, describes how the

uptake of nutrients by a growingpopulation of bacteria creates an ionicflux that can be used to trigger thedissolution of carrier particles andrelease of antimicrobial silver. Filmscontaining the smart particles havebeen shown to work effectively in thepresence of varioushumanpathogens,highlighting their potential for use inclinical environments. /lms

W. J. Stark et al., Small, DOI: 10.1002/smll.200800047

High-Quality Perfluoro-Pentacene Films Grown

In this Rapid Research Letter, StefanKowarik et al. present an in-situ andreal-time study of the growth ofperfluoro-pentacene (PFP). The penta-cene derivative PFP is a promisingn-type organic semiconductor withhigh electron mobility and is used incomplementary circuits with penta-cene. High structural order is found in

thin films as evidenced by Braggreflections up to the eighth order. Nocontamination with a second phase ispresent. The first order reflection isseen to increase with time. From adetailed analysis of the time-resolvedX-ray scattering the growth mode isdetermined to be Stranski-Krastanovgrowth with one wetting layer, andthe evolution of the surface roughnessis extracted. /sh

S.Kowarik et al.,phys. status solidi RRL2008,2, 120

Highly ReadArticlesHeterogeneous and Architectured Materials:A Possible Strategy for Design of StructuralMaterialsY. Brechet et al.Adv. Eng. Mater. 2008, 10, 24

Aniline Oligomers - Architecture, Function andNew Opportunities for NanostructuredMaterialsC. F. J. Faul et al.Macromol. Rapid Commun. 2008, 29, 280

LED to LEC Transition Behavior in PolymerLight-Emitting DevicesA. J. Heeger et al.Adv. Mater. 2008, 6, 1191

Polymer Electrolyte Membranes for the DirectMethanol Fuel Cell: A ReviewY. A. Elabd et al.J. Polym. Sci., Part B: Polym. Phys. 2006, 44, 2201

Interfacial Polymerization of MorphologicallyModified Polyaniline: from HollowMicrospheres to NanowiresJ. B. LiPolym. Int. 2008, 57, 337

Preparation of Biodegradable PolymerNanoparticles byMiniemulsion Technique andTheir Cell InteractionsK. Landfester et al.Macromol. Biosci. 2008, 8, 127

Protein Immobilization Using Atmospheric-Pressure Dielectric-Barrier Discharges: A Routeto a Straightforward Manufacture of BioactiveFilmsB. F. Sels et al.Plasma Processes Polym. 2008, 5, 186

Shape Control of Colloidal Metal NanocrystalsP. D. Yang et al.Small 2008, 4, 310

Syntheses, Properties, and PotentialApplications of Multicomponent MagneticNanoparticlesM. H. Zeng et al.Adv. Funct. Mater. 2008, 18, 391

Manufacturing Carbon Nanotube/PVDFNanocomposite PowdersA. Bismarck et al.Macromol. Mater. Eng. 2008, 293, 188

Modeling of Filtration throughMultiple Layersof Dual Scale Fibrous Porous MediaS. G. Advani et al.Polym. Compos. 2006, 27, 570

Materials Views 2008, June, A1–A8 � 2008 John Wiley & Sons, Inc. A3

Tailor-MadeSuperstructures

Much attention has been devoted tothe self-assembly of dendritic mole-cules to superstructures of controllabletopologies. Amphiphilic arborescent(or dendrigraft) copolymers are den-dritic molecules synthesized from poly-meric building blocks according to ageneration-based scheme. This articlein Macromolecular Chemistry andPhysics presents the first investigationof the self-assembly behavior of PS-g-PEO arborescent copolymers of highbranching functionalities at the air/

water interface using the Langmuirbalance technique. It could be shownthat arborescent PS-g-PEO copolymersform stable monolayers and tend toassociate spontaneously at the air/water interface even without com-pression. By varying the compositionand the structure of the arborescentPS-g-PEO copolymers, the associationbehavior of the amphiphiles could betailored to favor the formation of eitherribbon-like superstructures of uni-form width, large island-like clusterswith a wide size distribution, or non-associatedmicelles ofuniformsizes. /ks

M. Gauthier et al., Macromol. Chem. Phys.,DOI: 10.1002/macp.200700619

The Click. . . and How toUse it

Click chemistry is now a well-knownand widely used organic synthesistechnique. The specific chemistryimparted by the 1,2,3-triazole unit,however, has remained relativelyunexplored. Craig Hawker and co-workers describe an elegant methodfor the synthesis of 4-vinyl-1,2,3-tria-zoles that avoids theuseof a costly and

difficult protection step. AfterHuisgenreaction, a wide range of vinyl mono-mers with different functional groupscan be obtained by either Wittigor elimination chemistry. Since 1-H-triazole-based materials have shownpromise as catalytic supports andproton exchange membranes, thisreport provides a basis for furtherinvestigations by allowing access to arange of new materials. /gk

C. J. Hawker et al., J. Polym. Sci., Part A:Polym. Chem. 2008, 46, 2897.

Nanoworms for TumorTargeting

Cancer bionanotechnology is aimingfor two main goals: ultrasensitiveimaging for the early detection ofcancers and efficient delivery of thera-peutics to tumors. Dextran-coatedmagnetic iron oxide (IO) nanoparticlesare of particular interest because theyshow relatively low toxicity and longcirculation, and dramatically enhancehydrogen T2 relaxation in magneticresonance imaging (MRI). In this con-tribution in Advanced Materials M. J.Sailor et al. hypothesize that a nano-structure with an elongated assemblyof IO cores (called nanoworms NWs)would improve the ability of thenanoparticles to circulate, target, and

image tumors. Indeed, they find thatthe elongation of the nanoparticlesimproves their magnetic relaxivity inMRI, increases their ability to attach totumor cells in vitro, and amplifies theirpassive accumulation in vivo as com-pared to spherical ones. These resultsare important for the design of in vivomultifunctional nanoprobes applica-ble to the diagnosis and treatment ofhuman diseases. /ks

M. J. Sailor et al., Adv. Mater., DOI: 10.1002/adma.200800004

In BriefNovel "One-Step" Method forGraft CopolymersThe simultaneous ring-opening polymerization ofe-caprolactone and 2-hydroxyethyl methacrylatepolymerization via reversible addition fragmen-tation chain transfer chemistry lead to therespective graft-copolymer in one step. /ct

C. Barner-Kowollik et al., J. Polym. Sci. A: Polym.Chem., 2008, 46, 3058

Photocrosslinkable,Biodegradable ScaffoldsOptically transparent and biodegradable macro-mers based on poly(ethylene glycol) and fumaricacid copolymers can be photochemically cross-linked into biocompatible scaffolds, with poten-tial application in injectable, photocrosslinkablecarriers for drug and cell delivery. /df

M. Imami et al. Polym. Adv. Technol., DOI:10.1002/pat.1112

Diamond - Four Years after TcRead on where a newmodel system for electronicphase transitions stands in terms of control andunderstanding after boron-doping successfullyturned diamond into a superconductor. /sb

E. Bustarret, phys. status solidi a, DOI: 10.1002/pssa.200777501

New Insights intoBiodegradation of PLAMolecular ecological techniqueswere successfullyused to detect and identify new PLA-degradingmicroorganisms directly from the compost andmay provide a new tool for the investigation ofbiodegradation mechanisms and for recyclingprocesses of PLA and other biodegradable poly-mers. /ks

D. Y. Wu et al.,Macromol. Biosci. 2008, 8, 304

Responsive Gold NanoparticlesVia a two-step procedure surfactant-stabilizedgold nanoparticles are encapsulated by a poly-mer, leading to core/shell materials that exhibit atemperature-driven, reversible swelling-deswellingtransition. /gk

J. Perez-Juste et al., Adv. Mater. 2008, 20, 1666

Crosslinking ElectrospunNanofibersThorough mechanical characterization of cross-linked, electrospun chitosan-poly(ethylene oxide)nanofibermats demonstrate that themats becomemore brittle and less ductile after glutaraldehydevapor deposition crosslinking, and that mechan-ical properties can be tuned by adjusting thecrosslinking time. /df

C. L. Schauer et al., J. Appl. Polym. Sci., DOI:10.1002/app.28107

Materials Views 2008, June, A1–A8 � 2008 John Wiley & Sons, Inc. A5

A Colorful Response

Light-emitting organic polymers, withtheir attractive luminescence efficien-cies, response times and full-colordisplays, have been investigated asalternatives to their inorganic coun-terparts in a variety of devices such asdiodes, photodetectors or image sen-sors. The color of the light emitted canbe tuned by altering the electronenvironment - either during the prep-aration process of the polymer or aspost-functionalization. Liu and co-work-ers have for the first time exploitedradical addition reactions for this

purpose. The addition of free radicalsto double bonds of a poly(phenylenevinylene) backbone led to the forma-tion of single bonds, shortening thep-conjugated length of the polymerchains and resulting in a blue shift ofthe luminescence peak. By regulatingthe reaction extent, the researcherscould control the conjugation lengthof the polymer and therefore its wave-length of fluorescence. /ap

F.-Q. Liu et al., Polym. Int., DOI: 10.1002/pi.2428

Ultramicroscopy for aDetailed AnatomicInsight

Confocal and 2-photonmicroscopy bothallow excellent spatial resolution. Yet,

they suffer from limited fields of viewand a penetration depths of less than1 mm. To obtain 3D reconstructionsfrom large specimens, histologicalsections are still standard. A team ledby H.-D. Dodt developed a new tech-nique based on the 100-years-old ideaof light sheet illumination, termedultramicroscopy. The sample is later-ally illuminated by a blue laser form-ing a thin sheet of light. Fluorescenceis emitted only from a thin opticalsection and collected by the objectivelens. To clear opaque biological sam-ples, they are imbued with a mediumof the same refractive indexasprotein.The team presents ultramicroscopic3D-reconstructions ofwhole immuno-labeled mouse embryos and Droso-phila giving detailed insight into theiranatomy. /kmh

K. Becker et al., J. Biophot., DOI: 10.1002/jbio.200710011

Just Add Sugar:Microcapsule ContentRelease

Controlled release ofmicrocapsule con-tents such as pharmaceuticals, mono-mers, or messenger compounds isgarnering widespread interest frommedical applications to materialsengineering. Tatjana Levy, ChristopheDejugnat and Gleb Sukhorukov showa smart route to carbohydrate-sensitive films and microcapsules bycreating (mannan/PAA-BOH)7 multi-layers via LbL technique. Their stabil-ity arises from covalent but reversibleester bonds between the polysacchar-ide and phenylboronic acid moieties.Competitive binding of sugars andmannan to the boronic acid causescarbohydrate response, leading to swiftdissolution of themultilayer structurewhen exposed to carbohydrate con-centrations above a sugar-specificcritical level. Encapsulated rhod-amine-labeled bovine serum albuminserves as indicator for themultilayers’disintegration. The presented workshows promise for both carbohydratesensing aswell as sugar-sensitive deliv-ery systems, with the capsule contentas chemical amplifier or cargo. /mo

T. Levy et al., Adv. Funct. Mater., DOI:10.1002/adfm.200701291

MaterialsBestsellersW. D. CallisterFundamentals of Materials Science andEngineering: An Integrated Approach,3rd EditionISBN: 978-0-470-23463-1

G. Schmid (Ed.)Nanotechnology: Volume 1: Principles andFundamentalsISBN: 978-3-527-31732-5

J. N. Lalena, D. A. Cleary, E. Carpenter, N. F. DeanInorganic Materials Synthesis and FabricationISBN: 978-0-471-74004-9

A. Zuttel, A. Borgschulte, L. Schlapbach (Eds.)Hydrogen as a Future Energy CarrierISBN: 978-3-527-30817-0

E. Bauerlein, P. Behrens, M. Epple (Eds.)Handbook of Biomineralization, 3 Volume SetISBN: 978-3-527-31641-0

K. Gonsalves, C. Halberstadt, C. T. Laurencin,L. Nair (Eds.)Biomedical NanostructuresISBN: 978-0-471-92552-1

R. Riedel, I-W. Chen (Eds.)Ceramics Science and Technology: Structures,Volume 1ISBN: 978-3-527-31155-2

C. S. S. R. Kumar (Ed.)Nanomaterials for BiosensorsISBN: 978-3-527-31388-4

R. M. Feenstra, C. E. C. WoodPorous Silicon Carbide and Gallium NitrideISBN: 978-0-470-51752-9

F. Endres, D. MacFarlane, A. Abbott (Eds.)Electrodeposition from Ionic LiquidsISBN: 978-3-527-31565-9

T. Ohji, M. Singh, J. Salem, D. Zhu (Eds.)Advanced Processing and ManufacturingTechnologies for Structural andMultifunctional Materials IIISBN: 978-0-470-19638-0

M. Gupta, E. W. W. LeongMicrowaves and MetalsISBN: 978-0-470-82272-2

Materials Views 2008, June, A1–A8 � 2008 John Wiley & Sons, Inc. A7