What makes them unique Why do they have properties that aren't easily replicated by other materials Let's start with a property that you are probably familiar with. Therefore calculating the MW via a formula can be helpful.Ī commonly used calculation is the Mark-Houwink equation, also known as Mark-Houwink-Sakurada (MHS) equation, where viscosity may be known. The intrinsic viscosity related to polymer flow in a liquid is defined as : (1.7)(0c0)c0 where is measured solution viscosity, 0 is dilute. The viscosity average molecular weight (M v) of any unknown PASt sample may be estimated by first measuring the samples intrinsic viscosity, and then applying these and K values in the Mark. Chris Schaller College of Saint Benedict/Saint John's University Polymers have come to occupy a very important niche in the materials we use every day. With all this, it’s important that MW is calculated and known to effectively and efficiently construct ones chitosan-based system. In the case of chitosan-based hydrogels for example, MW impacts on the form and strength of the hydrogel and release rates of drug delivery systems. It can affect many properties of the material including but not limited to conformation, solubility, viscosity and cytotoxicity ). Molecular weight (MW) of chitosan is the mass of one mole of a substance and influences the physiochemical and rheology of the native chitosan and the materials produced with said chitosan. But this is a Quick Guide to determine MW of chitosan using the Mark-Houwink equation, where viscosity is known. There are several methods to determine the Mw of chitosan. Therefore determining and tuning chitosans’ MW can be critical in meetings a system’s target(s) in its application. The intrinsic viscosity () was determined via Huggins’ plot (i.e., the plot of sp /c versus c) based on Equation (1), where c was the cellulose concentration in unit of g/L, and K 1 is a constant. The determination of the intrinsic viscosity by single-point determinations, like that based on the SolomonCiuta equation, have been proposed as efficient alternatives to dilution procedures. In these equations, is solution viscosity, 0 is viscosity of the pure solvent, and c is concentration.
Chitosans’ MW, degree of deacetylation (DDA), high polydispersity index (PDI), and distribution of acetyl groups are important intrinsic factors of chitosan, which can affect its physicochemical properties, rheology, bioactivity, and interaction with co-materials and tissue. Commercial chitosan products are produced with different molecular weight (MW) typically ranging from 100 to 800 kDa.
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