3D Printing of Core–Shell Capsule Composites for Post‐Reactive and Damage Sensing Applications

Abstract

3D printing of multicomponent materials as an advantageous method over traditional mold casting methods is demonstrated, developing small core–shell capsule composites fabricated by a two‐step 3D printing process. Using a two‐print‐head system (fused deposition modeling extruder and a liquid inkjet print head), micro‐sized capsules are manufactured in sizes ranging from 100 to 800 µm. The thermoplastic polymer poly(ε‐caprolactone) (PCL) is chosen as matrix/shell material due to its optimal interaction with the embedded hydrophobic liquids. First, the core–shell capsules are printed with model liquids and pure PCL to optimize the printing parameters and to ensure fully enclosed capsules inside the polymer. As a proof of concept, novel “click” reaction systems, used in self‐healing and stress‐detection applications, are manufactured in which PCL composites with nano‐ and micro‐fillers are combined with reactive, encapsulated liquids. The so generated 3D printed core–shell capsule composite can be used for post‐printing reactions and damage sensing when combined with a fluorogenic dye.

3D Printing in Development of Nanomedicines

“…Middle layers were loaded with oil (linalool, limonene, trivalent alkyne, and farnesol) by inkjet print head, forming microsized capsules having a size range of 200–800 µm and containing nanocapsules. These capsules, designed by using 3D printing, showed thermal stability up to a temperature of 80 °C [ 79 ].…”

Synthetic polymer-derived single-network inks/bioinks for extrusion-based 3D printing towards bioapplications

“…Nanoengineered polymers are hybrid materials in which polymeric matrix are dispersed with one or more type of inorganic or organic nanofillers such as silica or metallic nanoparticles, nanoclay, nanorods, carbon nanotubes and nanofibers, graphene, metallic nanowires, quantum dots, etc. 98,99 Due to the several advantages imparted by the incorporated nanomaterials (via choosing proper mixing strategies) within the polymer matrix, such fabricated polymer nanocomposite materials exhibit significantly improved rheological performance, functionality and properties (for e.g., mechanical, electrical, optical, thermal, biological and magnetic properties) with respect to the native polymers, 100,101 and therefore, makes the polymer nanocomposite a suitable candidate to enable additive manufacturing based highly-customized complex and functional 3D constructs. with shape-fidelity and enhanced electrical conductivities >800 S/m for electronic applications.…”

Multicomponent Stress‐Sensing Composites Fabricated by 3D‐Printing Methodologies

“…The 3D‐printing method aims to directly dispense the liquid into a solid matrix during the FDM‐printing process, thus largely suppressing a primordial thermal activation of the “click” reaction during 3D‐printing. [ 38 ]…”

“…Similar to a procedure recently developed in our research group, [ 38 ] a 3D‐printed structure with a square‐shaped base of 5 × 5 mm and a grid with gaps of around 300 µm were designed in a BioCAD program. First the two layers of the 100% filled base area were printed using fused deposition modeling (FDM) for the PCL composite.…”

“…The 3D-printing method aims to directly dispense the liquid into a solid matrix during the FDM-printing process, thus largely suppressing a primordial thermal activation of the "click" reaction during 3D-printing. [38] The first step in the chemical design constituted the synthesis of a suitable mechanophore, able to be 3D-printed under preservation of its stress-reporting function. To this endeavor, we have prepared the copper(I)-bis(NHC)-mechanophores 1a, 1b, 1c (see Figure 2), where either a C11-chain (1a), a PCL-chain (1b), or an urethane (1c) are attached to the bis-N-heterocyclic-carbene (NHC)-Cu(I)-complexes as the active, mechanoresponsive elements.…”