Comparison of milling and solution approach for production of silk particles

•Surfactant assisted milling could produce particles with controllable sizes.•Volume average particle size of the milled particles could be reduced to 300 nm.•Regenerated particles tend to create large aggregates.•Milled particles have higher thermal decomposition temperature than regenerated ones.

Silk particles were produced by regenerating from silk solution, and using a milling method. In the regenerated silk particle production, two methods which are reported to render submicron silk particles were selected. Their particle sizes and structures were compared with particles of milling method already developed by us. The volume median average particle sizes (d(0.5)) of regenerated particles were much higher than what was reported previously. In contrast, milling method could produce particles with adjustable particle sizes ranging from micron to submicron level. All the milled particles had advantage of at least 15 °C higher thermal decomposition temperature than regenerated particles. They had silk II structure, and the crystallinity reduced as particle fineness increased, but remained higher than regenerated particles of similar sizes.

Graphical abstractSignificant differences in particle size, structure, and thermal degradation temperature were found for silk particles produced from surfactant assisted milling and regeneration methods. Milled particles have much higher thermal decomposition temperatures than regenerated ones.Figure optionsDownload full-size imageDownload as PowerPoint slide