Strong Orientation of Polymer Chains and Small Photochromic Molecules in Polyamide 6 Electrospun Fibers

Bianco, Andrea; Iardino, Giacomo; Manuelli, Alessandro; Bertarelli, Chiara; Zerbi, G.

doi:10.1002/cphc.200600657

Cited by 32 publications

(26 citation statements)

References 35 publications

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“…38,39 To ascertain this phenomenon in the present study, a mat of P(NDI2OD-T2) fibers aligned along a preferential uniaxial direction has been analyzed by polarized infrared spectroscopy, and a dichroic ratio different than 1 has been detected for some of the characteristic bands of P(NDI2OD-T2), namely 1705 and 1665 cm −1 . These results likely provide the first evidence of the preferential orientation of the polymer chains with respect to the fibers axis ( Figure S04).…”

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confidence: 99%

n-Type Semiconducting Polymer Fibers

et al. 2012

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Defect-free bicomponent fibers of poly{[N,N′-bis(2-octyl-dodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)}/poly(ethyleneoxide) P(NDI2OD-T2)/PEO are fabricated by means of electrospinning and rinsed with a selective solvent to afford pure P(NDI2OD-T2) while maintaining a fibrous morphology. The elongation strength applied on the spun jet by the high electrical field induces a preferential orientation of polymer chains. An electron mobility analogous to the best obtained with a thin film-based device is achieved in single fiber transistors, and the results are unaffected by the dielectric surface treatment

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confidence: 99%

n-Type Semiconducting Polymer Fibers

et al. 2012

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“…The jet is further stretched and thinned on the way to the collector due to electrostatic self repulsion. During the past few years a number of important advances in the technique were reported, such as fibre alignment, 5,6 tuning of fibre diameter from the nanometre to the micrometre range, 6 combination with sol-gel processes for the production of inorganic tubes, 7,8 and coaxial electrospinning of different polymers 9 or even of non-polymeric liquids in a polymer-inorganic composite sheath. 3,8 While the latter has so far been demonstrated using simple alkanes 3 or mineral oil, 8 such coaxial electrospinning opens the door to incorporation of a wide range of materials, including complex fluids, allowing for the introduction of new functionality to the fibre.…”

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confidence: 99%

Coaxial electrospinning of microfibres with liquid crystal in the core

et al. 2008

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Liquid crystal containing composite fibres were produced via coaxial electrospinning, demonstrating that this technique can be used for producing new functional fibres and/or to study the impact of extreme confinement on liquid crystal phases.Electrospinning offers a simple yet versatile means of producing nano-and microfibres of various materials and with properties tailored for use in diverse applications, ranging from photovoltaics 1 and photocatalysis 2 to energy storage 3 or tissue engineering. 4 By applying a DC voltage of several kV between a spinneret and a collector, a thin jet is ejected from a polymer melt or solution that is pumped through the spinneret. The jet is further stretched and thinned on the way to the collector due to electrostatic self repulsion. During the past few years a number of important advances in the technique were reported, such as fibre alignment, 5,6 tuning of fibre diameter from the nanometre to the micrometre range, 6 combination with sol-gel processes for the production of inorganic tubes, 7,8 and coaxial electrospinning of different polymers 9 or even of non-polymeric liquids in a polymer-inorganic composite sheath. 3,8 While the latter has so far been demonstrated using simple alkanes 3 or mineral oil, 8 such coaxial electrospinning opens the door to incorporation of a wide range of materials, including complex fluids, allowing for the introduction of new functionality to the fibre. As an example of such development we here report coaxial electrospinning of composite fibres consisting of a poly(vinylpyrrolidone) (PVP)/TiO 2 sheath and a nematic liquid crystal core.Liquid crystals constitute a unique class of liquids in that they combine fluidity with long-range order, orientational and in some cases also 1D or 2D translational. 10 This gives them a strong response to external influences, which is the basis for their very successful application in devices such as displays, modulators and sensors. The nematic phase exhibits only orientational order, described by the director n, a signless unit vector indicating the average direction of the principal symmetry axis of the molecules or molecule aggregates (rodor disclike). When incorporated into an electrospun fibre, the various types of self-assembled nano-and microstructures and the strong response function could provide the fibre with novel functionality, with potential application fields ranging from cheap temperature sensors to clothing with switchable textures. On the other hand, electrospinning such a composite fibre also constitutes a simple method of studying the effects of extreme confinement on various liquid crystal phases and phase transitions. Such effects can be very strong. 11,12 Our coaxial electrospinning set-up is schematically shown in Fig. 1. A small hole was made in the side of a syringe containing the outer fluid, allowing a flexible polyimide-coated silica capillary tube (outer diameter 320 mm) to be inserted and led through the needle of the syringe (inner diameter 500 mm). The hole was sealed with epo...

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“…A possible explanation is the larger surface area as well as a slower exchange of ions due to reduced diffusive flow inside the network. Additional contribution can be from the axial alignment of the PI chains shown to occur during electrospinning process [20], which can lead to decreased modification rate compared to the bulk film. From the SEM results it can be seen that both 30 min and 60 min subjection to 4 M KOH synthesize a Ag nanoparticle layer modification with a density that can act as an intermediate layer of higher surface energy to assist in proper wetting for the subsequent the infiltration.…”

Section: Optimization Of Imide-ring Cleavage On Electrospun Pi Fibresmentioning

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Fabrication and characterization of a metal matrix polymer fibre composite for thermal interface material applications

Zandén

et al. 2013

19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)

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Dealing with increasing power densities in high performance micro-and power -electronics applications is continuously becoming more challenging. Many applications today need thermal interface materials (TIMs) that can offer significantly higher performance than what is currently available. One of the main challenges for TIMs is to combine material properties that result in the thermo-mechanical characteristics required. Solder TIMs can provide excellent thermal transport, but high stiffness, causing lack of sufficient thermal-mechanical decoupling, limits their applicability. To mitigate these issues we pursue the development of a composite metal matrix based TIM technology concept with potential to combine high thermal conductivity with low joint stiffness. In this work we optimize the fabrication of an indium matrix polyimide fibre composite and investigate its thermal performance as an interface material. The fabricated composite is shown to have high effective thermal conductivity (up to 22 W/mK) and result in low contact resistance (<1 Kmm 2 /W).

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Strong Orientation of Polymer Chains and Small Photochromic Molecules in Polyamide 6 Electrospun Fibers

Cited by 32 publications

References 35 publications

n-Type Semiconducting Polymer Fibers

n-Type Semiconducting Polymer Fibers

Coaxial electrospinning of microfibres with liquid crystal in the core

Fabrication and characterization of a metal matrix polymer fibre composite for thermal interface material applications

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