Ilker S. Bayer

Italian Institute of Technology

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Athanassia Athanassiou

Italian Institute of Technology

Eric Loth

University of Virginia

José A. Heredia‐Guerrero

Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"

R. Cingolani

Italian Institute of Technology

Luca Ceseracciu

Italian Institute of Technology

Constantine M. Megaridis

University of Illinois Chicago

Abhijit Biswas

Indian Institute of Technology Gandhinagar

Adam Steele

Arizona State University

Despina Fragouli

Italian Institute of Technology

Alexander Davis

Italian Institute of Technology

Cooperative Institutions

Italian Institute of Technology

135

University of Genoa

Istituto Nazionale di Fisica Nucleare, Sezione di Genova

National Research Council

University of Illinois Urbana-Champaign

Center for Biomolecular Nanotechnologies

Polytechnic University of Turin

Centre National de la Recherche Scientifique

University of Virginia

University of Notre Dame

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Cocoa Shell Waste Biofilaments for 3D Printing Applications

Macromolecular Materials and Engineering (2017)

Thi Nga Tran Ilker S. Bayer José A. Heredia‐Guerrero Michela Frugone Marco Lagomarsino

Abstract In this study, biofilaments based on cocoa shell waste, a by‐product of the chocolate industry, and biodegradable poly(ε‐caprolactone), PCL, have been prepared using a single‐screw extruder. Micronized cocoa shell waste is compounded in the polymer up to 50% by weight without significant alteration of its crystalline structure. Resultant elastic (Young's) modulus of biofilaments remains close to that of pure PCL. Scanning electron microscopy results indicate that micronized cocoa shell waste is homogeneously dispersed in the polymer during the extrusion process. Detailed thermal characterization measurements on the extruded filaments allow tuning of the fused deposition modeling 3D printing parameters. 3D printed items display a well‐defined structure with good adhesion between deposition layers and fine resolution. Hence, with this simple and solvent‐free fabrication technique, uniformly structured cocoa shell waste biofilaments can be produced in a very reproducible manner and can be used in 3D printing of diverse objects with potential household and biomedical applications.

Fused Deposition Modeling

Characterization

Deposition

10.1002/mame.201700219

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Citations (97)

A Thermochromic Superhydrophobic Surface

Scientific Reports (2016)

Pietro Cataldi Ilker S. Bayer R. Cingolani Sergio Marras Ryad Chellali

Abstract Highly enhanced solid-state thermochromism is observed in regioregular poly(3-hexylthiophene), P3HT, when deposited on a superhydrophobic polymer-SiO 2 nanocomposite coating. The conformal P3HT coating on the nanocomposite surface does not alter or reduce superhydrophicity while maintaining its reversible enhanced thermochromism. The polymeric matrix of the superhydrophobic surface is comprised of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) copolymer and an acrylic adhesive. Based on detailed X -ray diffraction measurements, this long-lasting, repeatable and hysteresis-free thermochromic effect is attributed to the enhancement of the Bragg peak associated with the d -spacing of interchain directional packing (100) which remains unaltered during several heating-cooling cycles. We propose that the superhydrophobic surface confines π–π interchain stacking in P3HT with uniform d -spacing into its nanostructured texture resulting in better packing and reduction in face-on orientation. The rapid response of the system to sudden temperature changes is also demonstrated by water droplet impact and bounce back on heated surfaces. This effect can be exploited for embedded thin film temperature sensors for metal coatings.

Thermochromism

Hysteresis

Conformal coating

10.1038/srep27984

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Citations (25)

Environmentally Benign Production of Stretchable and Robust Superhydrophobic Silicone Monoliths

ACS Applied Materials & Interfaces (2017)

Alexander Davis Salvatore Surdo Gianvito Caputo Ilker S. Bayer Athanassia Athanassiou

Superhydrophobic materials hold an enormous potential in sectors as important as aerospace, food industries, or biomedicine. Despite this great promise, the lack of environmentally friendly production methods and limited robustness remain the two most pertinent barriers to the scalability, large-area production, and widespread use of superhydrophobic materials. In this work, highly robust superhydrophobic silicone monoliths are produced through a scalable and environmentally friendly emulsion technique. It is first found that stable and surfactantless water-in-polydimethylsiloxane (PDMS) emulsions can be formed through mechanical mixing. Increasing the internal phase fraction of the precursor emulsion is found to increase porosity and microtexture of the final monoliths, rendering them superhydrophobic. Silica nanoparticles can also be dispersed in the aqueous internal phase to create micro/nanotextured monoliths, giving further improvements in superhydrophobicity. Due to the elastomeric nature of PDMS, superhydrophobicity can be maintained even while the material is mechanically strained or compressed. In addition, because of their self-similarity, the monoliths show outstanding robustness to knife-scratch, tape-peel, and finger-wipe tests, as well as rigorous sandpaper abrasion. Superhydrophobicity was also unchanged when exposed to adverse environmental conditions including corrosive solutions, UV light, extreme temperatures, and high-energy droplet impact. Finally, important properties for eventual adoption in real-world applications including self-cleaning, stain-repellence, and blood-repellence are demonstrated.

Sandpaper

Environmentally Friendly

Polydimethylsiloxane

Abrasion (mechanical)

10.1021/acsami.7b15088

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Citations (120)

Inherently Superoleophobic Nanocomposite Coatings by Spray Atomization

Nano Letters (2008)

Adam Steele Ilker S. Bayer Eric Loth

We describe a technique to fabricate, for the first time, superoleophobic coatings by spray casting nanoparticle-polymer suspensions. The method involves the use of ZnO nanoparticles blended with a waterborne perfluoroacrylic polymer emulsion using cosolvents. Acetone is shown to be an effective compatibilizing cosolvent to produce self-assembling nanocomposite slurries that form hierarchical nanotextured morphology upon curing. Fabricated coating surface morphology is investigated with an environmental scanning electron microscope (ESEM), and surface wettability is characterized by static and dynamic contact angle measurements. The coatings can be applied to large and/or flexible substrates by spray coating with ease and require no additional surface treatments of commonly used hydrophobic molecules such as fluorosilanes; i.e., the nanocomposites are inherently superoleophobic. The superoleophobic nature of the coatings is also discussed within the framework of Cassie-Baxter and Wenzel wetting theories.

Biofouling

10.1021/nl8037272

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Superhydrophobic and conductive carbon nanofiber/PTFE composite coatings for EMI shielding

Journal of Colloid and Interface Science (2010)

Arindam Das Harun Taha Hayvaci Manish K. Tiwari Ilker S. Bayer Danilo Erricolo

10.1016/j.jcis.2010.09.017

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Citations (124)

Fabrication of Nanodielectric BaTiO<SUB>3</SUB> Composites Exhibiting Stable Capacitor Functions in the High Frequency (> 100 MHz) Through Interfacial Polarization Interactions

Nanoscience and Nanotechnology Letters (2009)

Abhijit Biswas Ilker S. Bayer A. Tripathi Evgeniya H. Lock Scott G. Walton

10.1166/nnl.2009.1024

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Spatially Controlled Surface Energy Traps on Superhydrophobic Surfaces

ACS Applied Materials & Interfaces (2013)

Athanasios Milionis Despina Fragouli Luigi Martiradonna George C. Anyfantis P. Davide Cozzoli

Water wetting and adhesion control on polymeric patterns are achieved by tuning the configuration of their surface's structural characteristics from single to dual and triple length-scale. In particular, surfaces with combined micro-, submicrometer-,and nanoroughness are developed, using photolithographically structured SU-8 micro-pillars as substrates for the consecutive spray deposition of polytetrafluoroethylene (PTFE) submicrometer particles and hydrophobically capped iron oxide colloidal nanoparticles. The PTFE particles alone or in combination with the nanoparticles render the SU-8 micropillars superhydrophobic. The water adhesion behaviour of the sprayed pillars is more complex since they can be tuned gradually from totally adhesive to completely non adhesive. The influence of the hierarchical geometrical features of the functionalized surfaces on this behaviour is discussed within the frame of the theory. Specially designed surfaces using the described technique are presented for selective drop deposition and evaporation. This simple method for liquid adhesion control on superhydrophobic surfaces can find various applications in the field of microfluidics, sensors, biotechnology, antifouling materials, etc.

Deposition

Polytetrafluoroethylene

Biofouling

Surface Modification

10.1021/am404565a

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Citations (54)

Rendering superhydrophobic laser-induced rough surfaces by transfering on them Teflon nanoparticles

TechConnect Briefs (2011)

A Athanassioua Ilker S. Bayer F. Brandi R. Cingolani

Source

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Networks of ultra-fine Ag nanocrystals in a Teflon AF^®matrix by vapour phase e-beam-assisted deposition

Nanotechnology (2007)

Abhijit Biswas Ilker S. Bayer B Marken Tyler D. Pounds M. Grant Norton

We have fabricated nanocomposite thin films comprising silver (Ag) nanoparticles dispersed in a Teflon AF® polymer matrix using electron-beam-assisted physical vapour deposition. Four different Ag nanoparticle volume fillings (20%, 35%, 70% and 75%) were achieved by varying the relative metal–polymer evaporation rates with the formation of highly crystalline Ag nanoparticles regardless of the filling ratio. The present fabrication technique allowed full control over dispersion uniformity of nanoparticles in the polymer network. At 20% and 35% metal volume fillings, the nanocomposite film morphology consists of a uniformly dispersed assembly of equiaxed isolated Ag nanoparticles. At higher metal volume fractions the nanocomposite structures displayed two different and unique Ag nanoparticle arrangements within the polymer matrix. In particular, at 70% metal filling, the formation of irregularly shaped clusters of individually assembled nanocrystals was observed. At a slightly higher volume filling (75%), larger irregularly shaped Ag nanocrystals that appeared to be the result of coalescence and grain growth were observed. Finally, a composite theory developed by Tandon and Weng was used to estimate various elastic properties of the nanocomposite films. At high metal filling, the reinforcing effect of the Ag nanoparticles was reflected as approximately a sixfold increase in the elastic modulus compared to the virgin polymer film. Possible applications of such ultra-fine metal nanoparticles networks are discussed.

10.1088/0957-4484/18/30/305602

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Effect of graphene nano-platelet morphology on the elastic modulus of soft and hard biopolymers

Carbon (2016)

Pietro Cataldi Ilker S. Bayer G. Nanni Athanassia Athanassiou Francesco Bonaccorso

10.1016/j.carbon.2016.08.026

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Citations (45)