Controlled partial embedding of carbon nanotubes within flexible transparent layers

Sansom, Elijah; Rinderknecht, Derek; Gharib, Morteza

doi:10.1088/0957-4484/19/03/035302

Cited by 19 publications

(16 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Tension test results showed consistently that the maximum normal tension force at failure was measured $2.3 N and in all cases failure always happened by the detachment of the PDMS polymer from the glass slide and never by debonding of the CNTs from the anchoring layer. These results are consistent with what was reported for similarly anchored CNTs in RTV layers [10] and confirm the excellent adhesion of the tubes with the thin substrate.…”

supporting

confidence: 92%

“…[4] In this work, we study the strain rate effects on the mechanical properties of carbon nanotube forests and report several related interesting new phenomena. We partially anchor [10] dense vertically aligned foam-like forests of carbon nanotubes on a thin, flexible polymer layer to provide structural stability, particularly at the higher strain rates. The goal of the anchoring was also to create versatile nanosystems, which integrate the excellent nanotube properties in a light-weight portable system.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Strain Rate Effects in the Mechanical Response of Polymer‐Anchored Carbon Nanotube Foams

2009

View full text Add to dashboard Cite

Super-compressible foam-like carbon nanotube films [1][2][3][4][5][6][7] have been reported to exhibit highly nonlinear viscoelastic behavior in compression similar to soft tissue. [4] Their unique combination of light weight and exceptional electrical, thermal, and mechanical properties have helped identify them as viable building blocks for more complex nanosystems and as stand-alone structures for a variety of different applications. In the as-grown state, their mechanical performance is limited by the weak adhesion between the tubes, controlled by van der Waals forces, and the substrate allowing the forests to split easily and to have low resistance in shear.[5] Under axial compression loading carbon nanotubes have demonstrated bending, buckling, [8] and fracture [9] (or a combination of the above) depending on the loading conditions and the number of loading cycles. [4] In this work, we study the strain rate effects on the mechanical properties of carbon nanotube forests and report several related interesting new phenomena. We partially anchor [10] dense vertically aligned foam-like forests of carbon nanotubes on a thin, flexible polymer layer to provide structural stability, particularly at the higher strain rates. The goal of the anchoring was also to create versatile nanosystems, which integrate the excellent nanotube properties in a light-weight portable system. We test the sample under quasi-static indentation loading and under impact loading and report a variable nonlinear response and different elastic recoveries with varying strain rates. A Bauschinger-like effect is observed at very low strain rates while buckling and the formation of permanent defects in the tube structure is reported at very high strain rates. Using high-resolution transmission microscopy we observe for the first time the delamination and crumbling of carbon nanotube walls. These polymer-anchored CNT foams are reported to behave as conductive nanostructured layers, suitable as fundamental building blocks for a variety of different applications, or as new self-standing application-ready materials with potential employment as actuators, impact absorbers, or as layered components for the creation of acoustic dampers.Because of the excellent thermal, electronic and mechanical properties, vertically aligned carbon nanotube (CNT) arrays have been proposed for several potential applications, ranging from biomimetic adhesives similar to spider's and gecko's feet, [11] to nanobrushes, [12] vibration damping layers, [6] and multifunctional composites, [13] but their development into successful commercial applications has been limited by their weak adhesion to the growth substrate, resulting in poor resistance to shear. In the present work we grew long, vertically-aligned multiwall CNTs (Fig. 1a), transferred and anchored them in thin polymer layers (Fig. 1b), and tested their mechanical response. While the nanotubes appear to be vertically aligned throughout the entire thickness of the sample (Fig. 1b), scanning electron microscopy (SEM) im...

show abstract

supporting

confidence: 92%

mentioning

confidence: 99%

Strain Rate Effects in the Mechanical Response of Polymer‐Anchored Carbon Nanotube Foams

2009

View full text Add to dashboard Cite

show abstract

“…Typically the vertical alignment is good at larger length scale and some entanglements present at smaller length scale. 1 After being exposed to UV/ozone or oxygen plasma treatment, the CNT arrays become hydrophilic and they can be wetted by water. A prolonged exposure to these treatments turns the CNT arrays superhydrophilic, indicated by their extremely low static contact angle of less than 30 °.…”

Section: Representative Resultsmentioning

confidence: 99%

Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays

Aria

Gharib

2013

JoVE

Self Cite

View full text Add to dashboard Cite

In this article, we describe a simple method to reversibly tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays. Here, CNT arrays are defined as densely packed multi-walled carbon nanotubes oriented perpendicular to the growth substrate as a result of a growth process by the standard thermal chemical vapor deposition (CVD) technique.1,2 These CNT arrays are then exposed to vacuum annealing treatment to make them more hydrophobic or to dry oxidation treatment to render them more hydrophilic. The hydrophobic CNT arrays can be turned hydrophilic by exposing them to dry oxidation treatment, while the hydrophilic CNT arrays can be turned hydrophobic by exposing them to vacuum annealing treatment. Using a combination of both treatments, CNT arrays can be repeatedly switched between hydrophilic and hydrophobic.2 Therefore, such combination show a very high potential in many industrial and consumer applications, including drug delivery system and high power density supercapacitors. 3-5The key to vary the wettability of CNT arrays is to control the surface concentration of oxygen adsorbates. Basically oxygen adsorbates can be introduced by exposing the CNT arrays to any oxidation treatment. Here we use dry oxidation treatments, such as oxygen plasma and UV/ozone, to functionalize the surface of CNT with oxygenated functional groups. These oxygenated functional groups allow hydrogen bond between the surface of CNT and water molecules to form, rendering the CNT hydrophilic. To turn them hydrophobic, adsorbed oxygen must be removed from the surface of CNT. Here we employ vacuum annealing treatment to induce oxygen desorption process. CNT arrays with extremely low surface concentration of oxygen adsorbates exhibit a superhydrophobic behavior. Video LinkThe video component of this article can be found at

show abstract

“…11 These systems have been suggested for several applications, including electronic 11,12 and field emission devices, 13 composites, 14,15 and bioactive materials. 16,17 The partial anchoring of vertical arrays of carbon nanotubes (VACNTs) in a single, thin polymer film has been previously reported, 18,19 and the mechanical response of anchored VACNTs has been characterized under quasi-static compressive loading. 19 Anchored VACNTs have been shown to behave as excellent light-weight energy absorbing systems.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear viscoelasticity of freestanding and polymer-anchored vertically aligned carbon nanotube foams

Lattanzi

Raney

Nardo

et al. 2012

Journal of Applied Physics

View full text Add to dashboard Cite

Vertical arrays of carbon nanotubes (VACNTs) show unique mechanical behavior in compression, with a highly nonlinear response similar to that of open cell foams and the ability to recover large deformations. Here, we study the viscoelastic response of both freestanding VACNT arrays and sandwich structures composed of a VACNT array partially embedded between two layers of poly(dimethylsiloxane) (PDMS) and bucky paper. The VACNTs tested are ∼2 mm thick foams grown via an injection chemical vapor deposition method. Both freestanding and sandwich structures exhibit a time-dependent behavior under compression. A power-law function of time is used to describe the main features observed in creep and stress-relaxation tests. The power-law exponents show nonlinear viscoelastic behavior in which the rate of creep is dependent upon the stress level and the rate of stress relaxation is dependent upon the strain level. The results show a marginal effect of the thin PDMS/bucky paper layers on the viscoelastic responses. At high strain levels (ɛ = 0.8), the peak stress for the anchored CNTs reaches ∼45 MPa, whereas it is only ∼15 MPa for freestanding CNTs, suggesting a large effect of PDMS on the structural response of the sandwich structures

show abstract

Controlled partial embedding of carbon nanotubes within flexible transparent layers

Cited by 19 publications

References 38 publications

Strain Rate Effects in the Mechanical Response of Polymer‐Anchored Carbon Nanotube Foams

Strain Rate Effects in the Mechanical Response of Polymer‐Anchored Carbon Nanotube Foams

Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays

Nonlinear viscoelasticity of freestanding and polymer-anchored vertically aligned carbon nanotube foams

Contact Info

Product

Resources

About