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Polymer Thin Films (polymer + thin_film)
Selected AbstractsGrayscale Photopatterning of an Amorphous Polymer Thin Film Prepared by Photopolymerization of a Bisanthracene-Functionalized Liquid-Crystalline MonomerADVANCED FUNCTIONAL MATERIALS, Issue 10 2010Hideyuki Kihara Abstract A method for grayscale photopatterning of an amorphous polymer film derived from a bisanthracene-functionalized liquid-crystalline monomer is developed. Solution photopolymerization of a monomer with two anthracene moieties, one at each end, affords an amorphous polymer. A combination of irradiation with patterned UV light and heating results in photopatterning on thin films prepared from the polymer. On non-irradiated areas of the film, the polymer reverts to the monomer owing to the thermal back-reaction of the anthracene photodimer, forming an ordered phase. On irradiated areas remaining in the amorphous phase, the thermal back-reaction is suppressed. This phenomenon results in a clear contrast and visual images on the film under polarized light. Grayscale photopatterning is also made possible for the solution-polymerized polymer by controlling the intensity of exposure. In addition, rewritable photopatterning can be achieved by melt photopolymerization of the monomer. The new photopatterning is essentially nondestructive because it needs neither image development nor anthracene-excitation light for reading. [source] Thermochemical Patterning of Polymer Thin Films With Tunable Size-Reduction Effects Using Metal-Coated Poly(dimethylsiloxane) StampsADVANCED MATERIALS, Issue 21 2009Fangfang Wang Metal-coated poly(dimethylsiloxane) (PDMS) stamps are treated as parallel microelectrodes to selectively induce thermochemical crosslinking of polymer thin films on Si substrates. Periodical polymer micro- and nanostructures with various size-reduction effects can be achieved by changing the conditions during metal deposition or modifying the surface of the metal-coated PDMS stamp. [source] High-Performance Programmable Memory Devices Based on Hyperbranched Copper Phthalocyanine Polymer Thin Films,ADVANCED MATERIALS, Issue 9 2008Seungchel Choi Electrically programmable fuse-type polymer memory devices based on hyperbranched copper phthalocyanine polymer thin films are fabricated. The devices have novel write-once-read-many (WORM) memory characteristics, with a high ON/OFF current ratio (of 106) and a high electrical stability, thus opening up the possibility of a low-cost mass production of high-performance, nonvolatile polymer memory devices. [source] Patterning a Poly(3,4-ethylenedioxythiophene) Thin Film Using a Liquid Crystalline Network,ADVANCED MATERIALS, Issue 3 2005O. Catanescu Polymerization and patterning of a conductive polymer thin film via a new approach involving a well-ordered polymer matrix previously obtained using a liquid-crystalline template is reported here. The resulting conductive polymer (PEDOT, poly(3,4-ethylenedioxythiophene)) was shown by scanning electron microscopy (SEM) to be very well aligned at a submicrometer level (see Figure). [source] Exploiting Chemical Switching in a Diels,Alder Polymer for Nanoscale Probe Lithography and Data Storage,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2006B. Gotsmann Abstract Reversibly crosslinked polymer films have properties that are beneficial to scanned-probe data storage and lithographic applications that use thermomechanical nanoindentation as a write or expose mechanism. The novel polymer under study contains linkages based on thermally reversible Diels,Alder crosslinking. Thermomechanical properties on the nanometer scale are analyzed by indentation experiments on polymer thin films using heated tips. The underlying indentation mechanism is studied at varying tip temperatures and indentation times, revealing Arrhenius kinetics. This is in contrast to the Williams,Landau,Ferry kinetics usually observed for polymer systems. The discrepancy is explained by the reversible crosslinking incorporated into the structure of the polymer that allows switching between two different states: a rigid, highly crosslinked, low-temperature state, and a deformable, fragmented, high-temperature state. An individual indentation volume of less than 10,20,L (10,000,molecule pairs) is estimated. These kinetics experiments demonstrate that a chemical reaction of only a few thousand molecules can be transduced into a mechanically measurable action. The ability to cycle between two sets of properties in these materials opens up new perspectives in lithography and data storage. Examples of data storage with densities up to 1,Tb,in.,2 and maskless lithography with resolution below 20,nm are demonstrated at writing times of 10,,s per bit/pixel. [source] Thermochemical Patterning of Polymer Thin Films With Tunable Size-Reduction Effects Using Metal-Coated Poly(dimethylsiloxane) StampsADVANCED MATERIALS, Issue 21 2009Fangfang Wang Metal-coated poly(dimethylsiloxane) (PDMS) stamps are treated as parallel microelectrodes to selectively induce thermochemical crosslinking of polymer thin films on Si substrates. Periodical polymer micro- and nanostructures with various size-reduction effects can be achieved by changing the conditions during metal deposition or modifying the surface of the metal-coated PDMS stamp. [source] High-Performance Programmable Memory Devices Based on Hyperbranched Copper Phthalocyanine Polymer Thin Films,ADVANCED MATERIALS, Issue 9 2008Seungchel Choi Electrically programmable fuse-type polymer memory devices based on hyperbranched copper phthalocyanine polymer thin films are fabricated. The devices have novel write-once-read-many (WORM) memory characteristics, with a high ON/OFF current ratio (of 106) and a high electrical stability, thus opening up the possibility of a low-cost mass production of high-performance, nonvolatile polymer memory devices. [source] A Simple Method for the Attachment of Polymer Films on Solid Substrates,ADVANCED MATERIALS, Issue 3 2003M. Yan The immobilization of polymer thin films on solid substrates has been achieved using a very simple method, involving spin coating the polymer, followed by UV irradiation. A robust film remains on the substrate surface after solvent extraction. The procedure could be employed to fabricate patterned polymer thin films via photolithography (see Figure). [source] Fluorescent, molecularly imprinted thin-layer films based on a common polymer,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Piotr Cywinski Abstract Fluorescent, molecularly imprinted polymer thin films, with cyclic guanosine 3,,5,-monophosphate (cGMP) as a template and 1,2-diphenyl-6-vinyl-1H -pyrazole-[3,4- b]-quinoline as a fluorescent receptor, were prepared according to a method based on commercially available poly (methyl methacrylate). This method of preparation predicts photoinduced crosslinking in the mixture of polymer chains and involved components. The advantages of this method are the relative simplicity of its preparation and the fact that a common polymer can be used. The spin-coated thin-layer films of imprinted and nonimprinted polymers were studied with the use of fluorescence microscopy with a scanning range of 80 × 80 ,m. A strong fluorescence quenching effect was observed when a cGMP-imprinted film was incubated in aqueous solutions of cGMP, but a comparatively small effect was observed for a nonimprinted polymer and when an imprinted film was incubated with cyclic adenosine 3,,5,-monophosphate (cAMP). The separation factor by the imprinted polymer was determined to be 2.55 for cGMP against cAMP. The obtained polymeric sensor appeared to be stable during subsequent measurements after rewashing and readsorption. The homogeneity of the surface of the polymer film, dependent on the method of film preparation, was also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 229,235, 2007 [source] Field-effect transistors based on PPV derivatives as a semiconducting layerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2009Woo-Hyung Lee Abstract A series of modified thiophene groups containing PPV-based semiconducting materials, poly[(2,5-bis(octyloxy)-1,4-phenylenevinylene)-alt-(2,2,bithienylenevinylene)] (PPBT), poly[(2,5-bis(octyloxy)-1,4-phenylenevinylene)-alt-(5,5-thiostilylenevinylene)] (PPTVT), have been synthesized through a Horner coupling reaction. From the FTIR and 1H NMR spectroscopy, the configuration of the vinylene groups in the polymers was all trans (E) geometry. The weight-average molecular weights (Mw) of PPBT and PPTVT were found to be 11,700 and 11,800, with polydispersity indices of 2.51 and 2.53, respectively. PPBT and PPTVT thin films exhibit UV,visible absorption maxima at 538 and 558 nm, respectively, and the strong absorption shoulder peaks at 578 and 602 nm, respectively. Solution processed field-effect transistors (FET) fabricated using all the polymers showed p -type OTFT characteristics. The field-effect mobility of the PPTVT was obtained up to 2.3 × 10,3 cm2 V,1 s,1, an on/off ratio of 1.0 × 105 with ambient air stability. Studies of the atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis of the polymer thin films revealed that all the polymers were amorphous structure. The greater planarity and rigidity of PPTVT compared to PPBT results in elongation of conjugation length and better ,,, stacking of polymer chains in amorphous region, which leads to improved FET performance. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 111,120, 2009 [source] Template-Directed Control of Crystal MorphologiesMACROMOLECULAR BIOSCIENCE, Issue 2 2007Fiona C. Meldrum Abstract Biominerals are characterised by unique morphologies, and it is a long-term synthetic goal to reproduce these synthetically. We here apply a range of templating routes to investigate whether a fascinating category of biominerals, the single crystals with complex forms, can be produced using simple synthetic methods. Macroporous crystals with sponge-like morphologies identical to that of sea urchin skeletal plates were produced on templating with a sponge-like polymer membrane. Similarly, patterning of individual crystal faces was achieved from the micrometer to nanometer scale through crystallisation on colloidal particle monolayers and patterned polymer thin films. These experiments demonstrate the versatility of a templating approach to producing single crystals with unique morphologies. [source] Neutron reflectivity of polymer-plasticiser diffusionMACROMOLECULAR SYMPOSIA, Issue 1 2002J.S. Higgins Neutron reflectivity (NR) has been widely exploited to look at polymer thin films and in many ways is an ideal technique for studying polymer interfaces and surfaces, providing high-resolution concentration - depth profiles across the film thickness. Most NR studies to date have concentrated on thin films of amorphous polymers which possess Tg values well above room temperature. These polymers are ideally suited to NR measurements, firstly because they form homogeneously flat films and, secondly, heat-quench cycles can be used to study time-dependent processes. This has been used to great effect in NR studies of the initial stages of polymer - polymer interdiffusion or the kinetics of surface segregated layers for instance. One of the biggest drawbacks to this approach is that in polymer systems where one or more of the components has a Tg close to or less than room temperature, the polymers can still move during the measurement time of an NR profile, which typically takes 1-2 h for a full profile. Therefore, in order to study such systems, we have developed an approach to NR measurements that allows us to investigate diffusion processes in situ. Our new approach allows us to take NR profiles in only 20 s. This paper describes the method of real-time NR measurements in detail and illustrates the capabilities of the technique with highlights from some of our recent work on the early stages of polymer-plasticiser interdiffusion. [source] Front Cover: Plasma Process.PLASMA PROCESSES AND POLYMERS, Issue 4-5 2006Polym. Front Cover: Organosilicon plasma polymer thin films undergo modifications as they are exposed to an oxygen plasma. Under well chosen oxygen plasma conditions, they can even be converted into SiO2 -like films as shown by FTIR transmission spectra and X-ray reflectometry measurements. Further details can be found in the Full Paper by A. Granier*, G. Borvon, A. Bousquet, A. Goullet, C. Leteinturier, and A. van der Lee on page 365. [source] | ||||||||||||||||||||||