3,4-Ethylenedioxythiophene (EDOT) End-Group Functionalized Poly-ε-caprolactone (PCL): Self-Assembly in Organic Solvents and Its Coincidentally Observed Peculiar Behavior in Thin Film and Protonated Media

Abstract

End-group functionalization of homopolymers is a valuable way to produce high-fidelity nanostructured and functional soft materials when the structures obtained have the capacity for self-assembly (SA) encoded in their structural details. Herein, an end-functionalized PCL with a π-conjugated EDOT moiety, (EDOT-PCL), designed exclusively from hydrophobic domains, as a functional “hydrophobic amphiphile”, was synthesized in the bulk ROP of ε-caprolactone. The experimental results obtained by spectroscopic methods, including NMR, UV-vis, and fluorescence, using DLS and by AFM, confirm that in solvents with extremely different polarities (chloroform and acetonitrile), EDOT-PCL presents an interaction- and structure-based bias, which is strong and selective enough to exert control over supramolecular packing, both in dispersions and in the film state. This leads to the diversity of SA structures, including spheroidal, straight, and helical rods, as well as orthorhombic single crystals, with solvent-dependent shapes and sizes, confirming that EDOT-PCL behaves as a “block-molecule”. According to the results from AFM imaging, an unexpected transformation of micelle-type nanostructures into single 2D lamellar crystals, through breakout crystallization, took place by simple acetonitrile evaporation during the formation of the film on the mica support at room temperature. Moreover, EDOT-PCL’s propensity for spontaneous oxidant-free oligomerization in acidic media was proposed as a presumptive answer for the unexpected appearance of blue color during its dissolution in CDCl3 at a high concentration. FT-IR, UV-vis, and fluorescence techniques were used to support this claim. Besides being intriguing and unforeseen, the experimental findings concerning EDOT-PCL have raised new and interesting questions that deserve to be addressed in future research.

Electroactive 3D printable poly(3,4-ethylenedioxythiophene)-graft-poly(ε-caprolactone) copolymers as scaffolds for muscle cell alignment

“…24 Apart from that, EDOT end-group functionalized PCL macromonomers, synthesized by ROP of hydrozymethyl-EDOT and Ɛ-caprolactone in presence of Sn(Oct) catalyst, has shown their ability to self-assemble in selective organic solvents due to their hydrophobic amphiphile nature. 25 In this work, we propose new PEDOT-g-PCL graft copolymers to manufacture electroactive scaffolds for muscle tissue engineering by DIW. These copolymers were synthesized through chemical oxidative polymerization of EDOT and new PCL macromonomers functionalized with an EDOT end group.…”

Thiophene α-Chain-End-Functionalized Oligo(2-methyl-2-oxazoline) as Precursor Amphiphilic Macromonomer for Grafted Conjugated Oligomers/Polymers and as a Multifunctional Material with Relevant Properties for Biomedical Applications

“…Constructed as an amphiphilic, π–aromatic group-ended system, as in the case of previous kindred structures [ 42 ], Th-OMeOx is expected to undergo SA in selective solvents, forming supramolecular structures [ 92 , 93 ]. Such a phenomenon, which can generate complexity at the nanoscale, can have implications on the properties both in solution and in films, and can influence Th-OMeOx ’s biological interactions.…”

“…These end-groups not only allowed the induction of properties that these flexible, commodity polymers never had [ 8 , 42 ] but greatly impacted the class of CPs, enabling the synthesis of grafted CPs (g-CPs) having well-defined oligomeric/polymeric side chains. Thus, the appearance of electroactive macromonomers afforded the movement of the so-called “solvent skin” concept of CP side groups beyond the solubility paradigm [ 43 ], while changing the classical amphiphilicity paradigm [ 44 , 45 ].…”

“…As such, exploration and synthesis of new electroactive and photoactive thiophene macromonomers, derived from oligo/polymers already known for their biocompatibility and/or biodegradability and able to work as synthons in the obtainment of new biomaterials, is an interesting current topic [ 29 , 30 , 41 , 42 ].…”

Surface‐Modified Melt Coextruded Nanofibers Enhance Blood Clotting In Vitro

“…[ 5,25 ] Properties that may improve biomedical outcomes can be enhanced by introducing bio‐active moieties onto the surface of the nanofiber. There are many potential functionalization methods of polyesters including end group modification, [ 26 ] hydrolysis, [ 27 ] aminolysis, [ 28 ] and photochemical covalent modification. [ 29 ] Chemical modification of nanofiber scaffolds has allowed for the fabrication of antifouling [ 30 ] and antibacterial mats, [ 5 ] as well as the creation of platforms for cellular adhesion, growth, proliferation, and differentiation mimicking the extracellular matrix (ECM).…”