Carbon-Based Polymers, Activated Carbons

Abstract

Carbon-based polymers and absorbents constitute a topic of huge scientific interest and great strategic importance in an interdisciplinary approach spanning applied physics, biology, pharmacy and medicine, mechanics, electronics, chemistry, and chemical engineering. Today carbon-based materials and adsorbents are widely used for energy storage and catalysis; for fabrication of electrodes and sensors operating in harsh environment; as hemoabsorbents of toxins and viruses in blood recovery; and as a biocompatible coating of medical implants, water purification, and wastewater treatment. Carbon is a surprisingly versatile element, able to hybridize in three different states, sp1, sp2, and sp3. The changes in local bonding of carbon atoms account for the existence of extremely diverse allotropic phases, exhibiting a very broad range of physical and chemical properties. This element can crystallize as diamond (sp3 hybridization) or graphite (sp2 hybridization) and give rise to many noncrystalline phases (generally containing a mixture of sp1, sp2, and sp3 hybridizations), such as fullerenes; carbon nanotubes; and disordered, nanostructured, and amorphous carbons. Strong tetrahedral δ bonds are responsible for the extreme physical properties of diamond, a wide gap semiconductor having the largest bulk modulus of any solid, the highest atom density, and the largest limiting electron and hole velocities of any semiconductor. Graphite, whose sheets (graphenes), featured by strong intralayer trigonal δ bonding, are held together by weak interlayer van der Waals’ forces, is considered as an anisotropic metal.