Self‐Organized Complex Patterning: Langmuir–Blodgett Lithography

Abstract

The integration of nanoscale features over macroscopic surface areas is a major challenge for traditional lithography. The vast majority of lithographic methods in use today either require the focusing of an incident beam onto a small area in order to minimize feature sizes in a parallel process or are based on a sequential process, [1] limiting either the minimum feature size or the throughput.[2] Even microcontact printing [3] and nanoimprint lithography [4] require the fabrication of a master. Self-organizing lithographic methods such as colloidal projections [5] (also known as ªnatural lithographyº [6] ), block-copolymer lithography [7±9] or the use of biomolecular arrays as lithographic resists [10] are exceptions in that they are capable of rapidly patterning a large area with lateral resolution in the nanometer range, albeit with limited complexity. The Langmuir±Blodgett (LB) [11] technique, in particular, has been used to prepare selforganized films of diblock copolymer micelles.[12] Furthermore, hierarchical arrays of aligned nanowires have been produced through a combination of LB film preparation with reactive ion etching (RIE) or photolithography. [13,14] Here we present methods to integrate complex LB patterns with nanometer-sized featured over macroscopic areas, e.g., 4 in. (1 in. = 2.54 cm) silicon wafers. We apply these self-pat-

Modelling the formation of structured deposits at receding contact lines of evaporating solutions and suspensions

“…Depending, e.g., on the velocity of the plate and the monolayer density on the trough, the transferred monolayer may exhibit stripe patterns parallel or perpendicular to the direction of withdrawal. [50][51][52] We will return to these experiments in the conclusion and discuss in which way our results may be related to these rather different systems.…”

Mechanism of Regular Pattern Formation in Reactive Dewetting

“…[1] These type of patterns have been recently observed in other monolayer systems [4] opening the possibility of extending LB lithography to other pattern-generating chemical systems. The patterns can be measured with scanning force microscopy (SFM) or optical microscopy, before or after etching the structures into silicon.…”

“…The patterns can be measured with scanning force microscopy (SFM) or optical microscopy, before or after etching the structures into silicon. [1] SFM of the unmodified LB film provides precise information about the line widths of the LB film, while the latter provides an easy way to visualize large surface areas. In this way the dynamics involved in the contact line motion can be recorded, thus providing insights into the mechanism of the pattern formation.…”

“…Langmuir-Blodgett (LB) lithography is a simple and rapid method for the generation of regular and/or complex chemical patterns over large surface areas; [1] for instance, substrate-induced condensation can produce striped patterns emerging from the LB transfer of phospholipids, such as l-a-dipalmitoylphosphatidylcholine (DPPC), from the air-water interface onto hydrophilic substrates at surface pressures well below the main phase-transition pressure. [2] Scanning force microscopy has shown that the transferred film consists of condensed DPPC stripes separated by regions covered by less dense DPPC molecules (channels).…”

Supramolecular Nanofibers by Self‐Organization of Bola‐amphiphiles through a Combination of Hydrogen Bonding and π–π Stacking Interactions

“…[1,2] Amphiphiles, gel-forming molecules, and other anisotropic compounds can all generate fibrous structures though self-organization in the medium in which they are dispersed, and some of these structures have potential as building blocks for biomolecular engineering or novel elements of molecular devices. [3][4][5][6] Among these self-organized structures, fibers formed by amphiphiles often have defined sizes and shapes at the nanometer scale, [7][8][9] and therefore this facile method for constructing fibers might have wider applications as an approach for the fabrication of self-organized soft matter. However, the potential practical applications of these nanostructures may be limited by their lack of stability and environmental reliability, due to the weakness of the hydrophobic interactions that hold the amphiphiles together.…”