High-Throughput Screening and Optimization of Photoembossed Relief Structures

Abstract

A methodology for the rapid design, screening, and optimization of coating systems with surface relief structures, using a combination of statistical experimental design, high-throughput experimentation, data mining, and graphical and mathematical optimization routines was developed. The methodology was applied to photopolymers used in photoembossing applications. A library of 72 films was prepared by dispensing a given amount of sample onto a chemically patterned substrate consisting of hydrophilic areas separated by fluorinated hydrophobic barriers. Film composition and film processing conditions were determined using statistical experimental design. The surface topology of the films was characterized by automated AFM. Subsequently, models explaining the dependence of surface topologies on sample composition and processing parameters were developed and used for screening a virtual 4000-membered in silico library of photopolymer lacquers. Simple graphical optimization or Pareto algorithms were subsequently used to find an ensemble of formulations, which were optimal with respect to a predefined set of properties, such as aspect ratio and shape of the relief structures.

Challenges and Progress in High‐Throughput Screening of Polymer Mechanical Properties by Indentation

“…Advanced data handling allowing facile visualization and/or mathematical description of the structure-processingproperty relationships present in the dataset. [72] After performing these five steps, one may use the obtained knowledge, the questions remaining, and/or the new questions that arose from the combinatorial experiment to design the next combinatorial experiment. [69] Alternatively, one can ''zoom in'' to a part of the parameter space that showed interesting ''leads'' or ''hits'', to identify even more optimal results by a finer-meshed investigation of that part of the parameter space.…”

“…[73,74] Design of experiment (step 1), advanced data handling (step 5), and proper integration of all steps of the combinatorial workflow significantly improve the information output of the experiment. [72] During combinatorial experiments, many different materials are made (step 2) but the amount of sample for each material is generally small. Typically, polymer amounts of 100 mg (an example from a polyolefin catalyst optimization study by Boussie et al [74] ) to 500 mg (sequential robot-assisted cationic ring-opening polymerization by Hoogenboom et al [75] ) are synthesized.…”

High aspect ratio surface relief structures by photoembossing

“…In current photoembossing, the aspect ratio, defined as the ratio of height and width, is typically less than 1/20 for a 40 m periodic line structure. 7,8 It was found that the material flux, and thus the aspect ratio, is highly affected by the polymerization kinetics and can be optimized by changing the rate of initiation via altering initiator content or light intensity. 9 It is the objective of our present research to improve the aspect ratio even further.…”

Light-Triggered Formation of Surface Topographies in Azo Polymers

“…Surface topographies and reliefs can be created in multiple ways, either by physically imprinting (embossing [15,16]) or by manipulation of the material itself using light, temperature, pH, and/or solvent-swelling. Interestingly, light allows for a remote, contactless approach without changing the chemical environment.…”