3D printing of highly flexible, cytocompatible nanocomposites for thermal management

Abstract

Highly flexible biocompatible materials that are both thermally conductive and electrically insulating are important for implantable and wearable bioelectronics applications. The ability to thermally process these materials into useful structures using additive manufacturing approaches opens up new opportunities for its use in bespoke structures. Here we investigate the three-dimensional (3D) printing of a medical-grade thermoplastic polyurethane (PU) elastomer, which is thermally insulating and enhance its thermal and mechanical properties through the incorporation of boron nitride (BN) as a filler. Via a simple solution compounding approach, a highly flexible and thermally conductive BN nanoparticle/ PU composite has been developed and subsequently processed into simple bio-scaffolds structures via a 3D pneumatic melt extrusion printing process. The addition of up to 20% w/w of BN to the PU significantly enhances the tensile modulus by 659%, from 1.74 to 13.2 MPa, while supporting high mechanical flexibility. The thermal conductivity of 20% w/w BN/PU composite increases by 74% with respect to the unmodified PU. The 3D printed BN/PU composite scaffolds exhibit good biocompatibility and cell attachment enhancement with L929 fibroblast cells.

3D Printed Boron Nitride Polyurethane Composites Electroosmotic Pump

“…The thermal conductivity of 0-20BNPU composites Thermal diffusivity (D, mm 2 /s) of 3D printed BNPU composites have been reported previously by our group [50] using a laser ash method (LFA-467 HyperFlash, NETZSCH, Germany) at 25 against a pyroceram reference sample to determine speci c heat capacity (C p , J/(g•K)) of the composites. Thermal conductivity of the composites λ (W/(m•K)) was calculated as λ = D × C p × ρ [51], where ρ is the density (g/cm 3 ).…”

“…Composites preparation and 3D-printing setup BNPU composites were prepared via a method previously reported [50]. PU pellets (HydroThane 80A, AdvanSource Biomaterials) were dissolved in a mixture of Ethanol/milli-Q water (85:15 v/v) at a concentration of 100 mg/mL under stirring in a water bath at 100°C for 4 h. BN nanopowders with a size of 150 nm (Sigma-Aldrich) were also dispersed in a solution of Ethanol/milli-Q water (85:15 v/v) under sonication for 1h.…”

Reliability of printed stretchable electronics based on nano/micro materials for practical applications

“…The printed filler structure is extremely attractive for achieving high heat transfer performance in composite materials because it reduces the number of filler-polymer interfaces, preventing future polymer-filler heat transfer, and most importantly, energy is transmitted throughout filler skeletons. 145,146 A complex network of filler skeletons offers adequate phonon transfer channels with plentiful interface points of contact, which might also efficiently play a vital role in improving the thermal conductance of polymeric composites. 147 These materials' attractiveness stems mostly from their large heat conductivities, significant specific surface regions, low weights, and outstanding overall capability.…”

A Review on Printing of Responsive Smart and 4D Structures Using 2D Materials

“…[36] Indeed, 3D printing of GRM composites and inks has already been applied to thermal management, [37] supercapacitors, [38][39] batteries, [39] conductors, [40][41][42][43][44] composites, [43,[45][46][47][48] aerogels, [49] and scaffolds, [50] amongst others, and is a field with hundreds of paper published in the last few years (Figure 1a) and already thoroughly reviewed. [41,[50][51][52][53] Recently, other composites and inks containing 2D nanomaterials such as MXenes and hexagonal boron nitride were 3D printed for energy storage [54][55][56] and thermal management [57][58] applications, respectively.…”