Stationary phases with precisely ordered morphology have the potential to drastically improve the performance of chromatographic operations, both in the analytical and in the preparative/industrial fields. The recent wave of additive manufacturing, aka 3D printing, gives the unprecedented ability to fabricate such stationary phases and to experimentally prove the theoretical principles of ordered chromatographic beds. The manufacture of highly efficient chromatographic columns is becoming a reality as 3D printers become more affordable and accessible, and their resolution, speed, and material flexibility continue to grow. This brings fresh ideas to the design of chromatographic beds, moving away from stereotypical "packed" beds with spherical particles to bespoke monolithic structures to suit a range of specific applications. This review aims to cover the state of the art of ordered beds for liquid chromatography applications, drawing analogies between the well-established pillar-array columns in two dimensions to their three-dimensional counterparts. The potential use of 3D printing to create entirely new column formats and cartridge designs such as microchip columns will also be discussed. Finally, key opportunities and challenges which remain in the field of 3D-printed chromatography are summarised, with the hope that 3D printed chromatographic columns will soon become the standard.

Flow boiling is a promising method for the cooling of sensitive computational and industrial components, facilitating the transportation of large quantities of heat at near-constant temperature and in a small form factor. The prevention of vapor film formation is a fundamental challenge for the enhancement of boiling systems, and an impetus therefore exists for the discovery of new techniques to segregate nucleating bubbles during their formation. Herein, we utilize the strong capillary forces generated by nanostructures to pin the liquid/vapor interface in three dimensions and thereby control the coalescence and flow interactions of developing bubbles. We demonstrate this principle on both symmetrical and asymmetrical superbiphilic microstructures, showing enhancement of peak heat transfer coefficient by 81% and 113%, respectively, when compared to the best superhydrophilic and superhydrophobic analogues. Our approach shows a potential future direction for engineered boiling micro/nanostructures, wherein bubble dynamics are directly manipulated on bespoke, three-dimensional substrates.

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