Innovation in Layer-by-Layer Assembly

Abstract

Methods for depositing thin films are important in generating functional materials for diverse applications in a wide variety of fields. Over the last half-century, the layer-by-layer assembly of nanoscale films has received intense and growing interest. This has been fueled by innovation in the available materials and assembly technologies, as well as the film-characterization techniques. In this Review, we explore, discuss, and detail innovation in layer-by-layer assembly in terms of past and present developments, and we highlight how these might guide future advances. A particular focus is on conventional and early developments that have only recently regained interest in the layer-by-layer assembly field. We then review unconventional assemblies and approaches that have been gaining popularity, which include inorganic/organic hybrid materials, cells and tissues, and the use of stereocomplexation, patterning, and dip-pen lithography, to name a few. A relatively recent development is the use of layer-by-layer assembly materials and techniques to assemble films in a single continuous step. We name this "quasi"-layer-by-layer assembly and discuss the impacts and innovations surrounding this approach. Finally, the application of characterization methods to monitor and evaluate layer-by-layer assembly is discussed, as innovation in this area is often overlooked but is essential for development of the field. While we intend for this Review to be easily accessible and act as a guide to researchers new to layer-by-layer assembly, we also believe it will provide insight to current researchers in the field and help guide future developments and innovation.

Spin-LbL Assembled Coatings of SiO2 and TiO2 oppositely Charged Nanoparticles for Superhydrophilicity, Antifogging and Antireflection

“…Electrostatic layer-by-layer (LbL) assembly has proven to be a simple, green and effective method to produce various kinds of coatings [10][11][12] . It can provide sufficient control over the thickness (in nanoscales) and structure of the coating to obtain AR properties, and therefore, wavelengths for maximum transmittance (antireflection) can be turned over the entire visible region by simply controlling the number of deposited bilayers.…”

“…It can provide sufficient control over the thickness (in nanoscales) and structure of the coating to obtain AR properties, and therefore, wavelengths for maximum transmittance (antireflection) can be turned over the entire visible region by simply controlling the number of deposited bilayers. Dip-LbL, Spray-LbL and Spin-LbL are often used to produce various ultra-thin coatings [7,10,13] . However, the drawback of DipLbL is time consuming; Spray-LbL is difficult to control the uniformity of a coating thickness.…”

“…For this reason, we have employed a Spin-LbL assembly method to rapidly produce thin Antifogging (AF) and AR coatings [13] . [3,10] . Therefore we used them as building blocks for fabricating the coatings.…”

Anti-Corrosive and Scale Inhibiting Polymer-Based Functional Coating with Internal and External Regulation of TiO2 Whiskers

“…In addition, the microcapsule shell should disintegrate to release the encapsulated agents [16]. Layer-by-layer assembly particle systems have received intense and growing attention in the past few years, but the complex techniques required have seriously compromised their scale-up manufacturing and applications [17]. Hence, it is necessary to develop physically and chemically stable porous carriers for the surface coating industry.…”

A Biocompatible Multilayer Film from an Asymmetric Picolinium‐Containing Polycation with Fast Visible‐Light/NIR‐Degradability

“…Layer‐by‐layer (LbL) assembly is a powerful and versatile technique to facilely prepare multilayered materials and precisely tailor the surface properties with low‐cost laboratory equipment . To date, this green LbL method has been used in a broad spectrum of fields spanning from controlled delivery systems, tissue engineering, separation, energy storage devices to electronics and food packaging .…”