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Interpolymer Complexes
Interpolymer complexes (IPC) are the products of non-covalent interactions between complementary unlike macromolecules in solutions. There are four types of these complexes: * Interpolyelectrolyte complexes (IPEC) or polyelectrolyte complexes (PEC) * Hydrogen-bonded interpolymer complexes * Stereocomplexes * Charge-transfer complexes Formation of interpolymer complexes Interpolymer complexes can be prepared either by mixing complementary polymers in solutions or by matrix (template) polymerisation. It is also possible to prepare IPCs at liquid-liquid interfaces or at solid or soft surfaces. Usually the structure of IPCs formed will depend on many factors, including the nature of interacting polymers, concentrations of their solutions, nature of solvent and presence of inorganic ions or organic molecules in solutions. Mixing of dilute polymer solutions usually leads to formation of IPCs as a colloidal dispersion, whereas more concentrated polymer solutions form IPCs in the form of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macromolecule
A macromolecule is a "molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass." Polymers are physical examples of macromolecules. Common macromolecules are biopolymers (nucleic acids, proteins, and carbohydrates). and polyolefins (polyethylene) and polyamides (nylon). Synthetic macromolecules Many macromolecules are synthetic polymers (plastics, synthetic fibers, and synthetic rubber. Polyethylene is produced on a particularly large scale such that ethylene is the primary product in the chemical industry. Macromolecules in nature * Proteins are polymers of amino acids joined by peptide bonds. * DNA and RNA are polymers of nucleotides joined by phosphodiester bonds. These nucleotides consist of a phosphate group, a sugar ( ribose in the case of RNA, deoxyribose in the case of DNA), and a nucleotide base (either adenine, guan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyelectrolyte
Polyelectrolytes are polymers whose repeating units bear an electrolyte group. Polycations and polyanions are polyelectrolytes. These groups dissociate in aqueous solutions (water), making the polymers charged. Polyelectrolyte properties are thus similar to both electrolytes ( salts) and polymers (high molecular weight compounds) and are sometimes called polysalts. Like salts, their solutions are electrically conductive. Like polymers, their solutions are often viscous. Charged molecular chains, commonly present in soft matter systems, play a fundamental role in determining structure, stability and the interactions of various molecular assemblies. Theoretical approaches to describe their statistical properties differ profoundly from those of their electrically neutral counterparts, while technological and industrial fields exploit their unique properties. Many biological molecules are polyelectrolytes. For instance, polypeptides, glycosaminoglycans, and DNA are polyelectrol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dispersion (chemistry)
A dispersion is a system in which distributed particles of one material are dispersed in a continuous phase of another material. The two phases may be in the same or different states of matter. Dispersions are classified in a number of different ways, including how large the particles are in relation to the particles of the continuous phase, whether or not precipitation occurs, and the presence of Brownian motion. In general, dispersions of particles sufficiently large for sedimentation are called suspensions, while those of smaller particles are called colloids and solutions. Structure and properties It is widely assumed that dispersions do not display any structure; i.e., the particles (or in case of emulsions: droplets) dispersed in the liquid or solid matrix (the "dispersion medium") are assumed to be statistically distributed. Therefore, for dispersions, usually percolation theory is assumed to appropriately describe their properties. However, percolation theory ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, transports it to another location where it is deposit (geology), deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by Solvation, dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and Wind wave, waves; glacier, glacial Plucking (glaciation), plucking, Abrasion (geology), abrasion, and scour; areal flooding; Aeolian processes, wind abrasion; groundwater processes; and Mass wastin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
