Dopamine as a bioinspired adhesion promoter for the metallization of multi-responsive phase change microcapsules

Abstract

This work reports on an environmentally friendly method to produce encapsulated phase change material with a thin nickel coating, applicable for heat conversion, storage and thermal management of heat-sensitive components and suitable for active heating by electromagnetic radiation. A critical issue for the metallization is the adhesion between the polymer capsule shell and the metal layer. Based on previous studies using the bio-molecule dopamine as adhesion promoter in composites and for plastics metallization, commercial paraffin microcapsules were coated with an ultrathin polydopamine film via a simple wet chemical process. Subsequently, a thin, uniform and compact nickel layer was produced by electroless metallization. The successful deposition of both layers was verified with a broad range of imaging and spectroscopic techniques. For the first time, surface-enhanced IR spectroscopy was used to study the deposition of ultrathin PDA films. The combination of SEM and energy-dispersive X-ray spectroscopy allowed resolving the spatial distribution of the elements Ni, N, and O in the MC shell. Electrically conducting paths in the Ni shell were verified by conductive AFM. Thermal analysis revealed that the coated microcapsules show a phase change enthalpy of approx. 170 J/g, suitable for thermal storage and management. Additionally, the nickel layer enhanced the thermal diffusivity of the microcapsule powders and enables a fast heating of the PCM microcapsules by microwave radiation, demonstrating the applicability of the metallized MCs for controlled heating applications. Graphical abstract

Improve the thermal properties of oil‐loaded polysulfone microcapsules by optimizing copper layer for self‐lubricating polyamide

“…PDA was formed by self‐polymerization of dopamine. The polymerization time had a certain effect on the adhesion properties of the final prepared copper layer on the surface of microcapsules 44,45 . Under the optimal sensitization conditions discussed above, the SEM morphologies of the PAO@PSF/Cu microcapsules prepared by changing the polymerization time of dopamine (1, 2, 5, 10, 18 h) were shown in the Figure 3.…”

“…The polymerization time had a certain effect on the adhesion properties of the final prepared copper layer on the surface of microcapsules. 44,45 Under the optimal sensitization conditions discussed above, the SEM morphologies of the PAO@PSF/ Cu microcapsules prepared by changing the polymerization time of dopamine (1, 2, 5, 10, 18 h) were shown in the Figure 3. When the polymerization time was 1 h, part of the copper layer formed on the surface of the PSF microcapsules fallen off from the microcapsule as shown in Figure 3A,A 1 , indicating that there was no good adsorption between the copper layer and the PSF shell of the microcapsule.…”

Biodegradable polymer composite containing ground corn stalk modified with polydopamine

“…The enhancement of adhesion between the polymer matrix and corn stalk particles, following the deposition of a polydopamine layer on the filler particles, is likely responsible for the improved tensile and flexural strength. Thanks to its unique chemical structure and diverse chemical groups 20,28 polydopamine easily combines with both the polymer matrix and filler particles, increasing the transfer of stress inside the material and thus improving the mechanical properties of materials with a modified corn stalk.…”