Molecular Interactions in Electrospinning: From Polymer Mixtures to Supramolecular Assemblies

Abstract

Electrospinning is growing as a production technology for many applications, particularly in membranes and tissue engineering. One challenge in electrospinning is the need for high molecular weight polymers, a requirement that often prevents formation of fibers with high proportions of functional materials that may include particles, surfactants, cells, etc. Molecular interactions between lower molecular weight polymers or molecules can provide similar cohesion in the electrospinning jet as entanglements from high molecular weight polymers. This review covers the existing studies of molecular interactions in electrospinning, providing a comprehensive analysis of the different approaches and outlook for the future. Three major categories are discussed: polymer–polymer molecular interactions (such as electrospinning of coacervates or interacting polymer blends), polymer–small molecule interactions (including cross-linking agents or particles mixed with the polymer), and supramolecular polymer electrospinning (cycodextrins, micelles, etc.). Significant attention is paid to the rheology of the polymer solutions and the electrospinning phase diagrams as well as to how these advances expand the use of electrospinning for target applications.

Microparticle Formation via Tri-needle Coaxial Electrospray at Stable Jetting Modes

“…As previously reported 31,32 , during single-needle electrospray, molecular weight of the solution influences the jetting status as shown in Equation 3:…”

An Overview of Biopolymeric Electrospun Nanofibers Based on Polysaccharides for Wound Healing Management

“…Furthermore, other critical factors that cause a polymeric solution to be subjected to the process of ellectrospinning in order to form eNFs are the molecular interactions: Polymer–polymer conjunction, polymer-small molecules (nanoparticles, additives, or salts, etc. ), and supramolecular polymers-small molecules [ 139 ]. The process of electrospinning gums with high molecular weight is demanding as a consequence of their heterogeneity, polydispersity, and abounding functional groups such as –NH 2 , –CO, –OH, –COOH, etc.…”

Advances in Fabricating the Electrospun Biopolymer-Based Biomaterials

“…Another issue affecting the polymer–solution interactions is the tendency of some of the materials to assemble into the larger aggregates or to form chemical interactions with different components of the solution. Chemical interactions that take place in the solution, both those that occur spontaneously and those that are intentionally introduced, have been extensively evaluated and described in a recent study by Elena Ewaldz and Blair Brettmann [ 20 ]. The polymers that tend to form such interactions do not obey typical laws established for the ES—for example, the thickness of the fibers cannot be strictly controlled, the gelling can occur or generally non-spinnable solutions can become spinnable.…”

“…The polymers that tend to form such interactions do not obey typical laws established for the ES—for example, the thickness of the fibers cannot be strictly controlled, the gelling can occur or generally non-spinnable solutions can become spinnable. One example of naturally occurring self-assembling biopolymers are phospholipids [ 21 ], but this phenomenon is also observed in cyclodextrins or tannic acid [ 20 ]. It is worth noting that knowledge about self-assembly can be harvested for designing the materials to meet the specific needs.…”