Production of Carbonaceous Materials with Various Lengths in Small Spheroidal Fullerenes and Long CNTs by Tunable Multi‐walled Carbon Nanotube Cutting

Abstract

Tunable cutting of multi-walled carbon nanotubes (CNTs) using high pressure homogenizer and/or HNO 3 /H 2 SO 4 solution was accomplished, resulting in the production of short CNTs with minimum length of 35 nm. Field emission scanning electron microscopy (FE-SEM) and Zeta sizer analysis showed significant reduction of CNT length from this tunable cutting (e.g. from long and entangled pristine CNTs at about 20 μm to ≥1000 nm,~400 nm,~200 nm, and~100 nm via high pressure jet-spraying cutting within 5 h, while chemical cutting process using greatly longer hours (48 h) showed a reduction only to about 1000 nm). When CNT sample of average 1000 nm length previously shortened by HNO 3 /H 2 SO 4 was subjected to the high pressure jet-spraying cutting process, the reduction progressed faster (≤1 h), producing ≥35 nm. Fourier transform infrared spectra and thermogravimetric analysis (TGA) indicated restricted formation of hydrophilic functional groups such as carboxylic group and hydroxyl group in the high pressure jet-spraying cutting, whereas an intensive formation of hydrophilic functional groups on the surface of shortened CNT samples was found after chemical cutting. Such short CNT samples would fulfill the requirements for carbonaceous materials with various lengths in small spheroidal fullerenes and long CNTs. The short CNTs produced are promising for scientific and technological applications in many fields such as electronics, diagnostics, pharmaceuticals, biomedical engineering, and environmental or energy industries.

Cutting Methods and Perspectives of Carbon Nanotubes

“…In the past few decades, researchers have used various physical methods to cut CNTs. − Generally speaking, these methods can be divided into two categories: mechanical cutting and electrical cutting. The mechanical cutting of CNTs usually refers to the destruction of CNTs under a mechanical force.…”

Positively and Negatively Charged Collagen Nanohydrogels: pH‐responsive Drug‐releasing Characteristics

“…Carboxyl group‐functionalized (CNT‐COOH, 0.5 μm length, negatively charged) and amine‐functionalized (CNT‐NH 2 , 0.5 μm length, positively charged) CNTs used in this experiment were prepared according to the reference . In brief, CNT‐COOH of approximately 1000 nm average length was prepared by acid oxidative method.…”

Detection of Individual Molecules and Ions by Carbon Nanotube‐Based Differential Resistive Pulse Sensor

“…The uniformity of long CNTs facilitates transport mechanisms unique in nanospace, such as ultrafast transport of molecules due to the superhydrophobic interior surface of CNTs and special phase transition of water in nanotubes . The TPa‐level Young's modulus and high chemical inertness properties are favorable to practical applications preventing mechanical deformation and chemical deterioration . Furthermore, synthesis of ultralong CNTs by methods such as chemical vapor deposition (CVD) is more productive and less expensive than that of the solid‐state nanopores.…”