Fast, simple and efficient assembly of nanolayered materials and devices

Abstract

A new method of 'directed' self-assembly is demonstrated that has the potential to simply and quickly build nanostructured materials and devices. Called spin-spray layer-by-layer self-assembly (SSLbL), it is a modification of the well-known layer-by-layer method (LbL). Using SSLbL, it is possible to create and stack nanometre-thick, uniform layers containing a wide variety of different polymers, nanoparticles, or colloids in less than 25 s per bilayer, orders of magnitude faster than traditional LbL. This is done by modifying traditional dipping LbL to a system where carefully chosen volumes of polymer or colloidal solutions are sprayed directly on a rotating substrate. SSLbL is also much less wasteful of valuable nanoparticles and polymers than LbL. It is shown that in contrast to less than 1% material usage found in LbL, SSLbL has material usage efficiency up to 50%, and this can be further improved. Another direct result of the spin-spray modification is simple control of the in-plane structure of nanolayered films using masks, which is demonstrated. Such capability opens up the possibility of simply and inexpensively building complete nanocomposite devices with both vertical and lateral organization.

Technology-driven layer-by-layer assembly of nanofilms

“…In spray assembly, the film properties-such as the morphology, uniformity, chemical composition, and selective membrane properties-can be tailored to be similar to those prepared by immersive assembly, with the film thickness influenced by suspension concentration, spray flow rate, spray duration, resting duration, whether or not the substrate is washed and for how long, and whether the solution is sprayed vertically or horizontally (16,51,(55)(56)(57). This control arises from the two main forces governing the spray assembly process, namely, bulk movement in the actual spray and random movement in the liquid film (56).…”

Spray‐Assisted Polyelectrolyte Multilayer Buildup: from Step‐by‐Step to Single‐Step Polyelectrolyte Film Constructions

“…[70] In this method the substrate is continuously rotated (typical rotation speed 3000 rpm). A first solution is then sprayed on the substrate for a precise time duration.…”

Rapid and efficient sprayed multilayer films for controlled drug delivery

“…As addressed in several reviews, Spray‐LbL has made a number of technological advancements since its humble demonstration with manually operated “plant misters.” Notable advances include the adaptation to a spinning substrate, automation to allow for higher speeds, improved handling for greater investigative power, application of flow with a vacuum gradient allowing for asymmetric coatings of porous substrates, and the use of simultaneous spraying . Its versatility has led to industrial, continuous roll‐to‐roll fabrication capable of large scale, high throughput production (19,440 m 2 /h) .…”