A glass-reinforced epoxy laminate is referred to as FR4 by NEMA. The material is made up of several layers. A glass fiber braided into a thin cloth-like sheet is the most basic layer. The glass fibers provide the structural support that FR4 requires. A flame retardant epoxy resin surrounds and bonds the innermost glass fiber layer. The most common grade of dielectric material used in the fabrication of circuit boards is the FR4 substrate, which is an electrical insulator with high dielectric strength.
In a wide range of applications, FR4 substrates with functional surfaces can give numerous performance advantages. Alfa Chemistry provides FR4 substrates with unique functionalized surface coating services. You can adjust the surface attributes of nearly any FR4-related product using our wide and simple surface modification procedures. You can confidently adjust the surface of your product if you choose to work with us!
Extensive Surface Modification Technology Options
Alfa Chemistry offers a number of polymer surface coating methods that can be used to functionalize the surface of FR4 materials in various ways in order to improve their varied surface properties. Among our surface modification technology choices are, but are not limited to:
- Surface waterproof coating technology - We can hydrophobic and oleophobic functionalize the FR4 substrate surface to make it highly water and oil repellent, effectively making it impervious to all liquids.
- Hydrophilic coating technology - By functionalizing the FR4 substrate's surface, we were able to make it very hydrophilic.
- Lubrication coating technology - We were able to reduce surface friction by lubricating functionalized FR4 substrate surfaces.
We can create chemically stable, optically clear, and long-lasting nanoscale coatings.
Learn more about our hydrophobic and oleophobic coatings.
Learn more about our hydrophilic coatings.
Learn more about our lubricant coatings.
Alfa Chemistry Coating Solution Cases
Case 1: Stable Hydrophilization of FR4 Substrates
The technology of lab-on-a-chip (LOC) is widely used and quickly growing. To solve the problem of seamless integration of microfluidics with other components such as sensors and electronic devices, printed circuit board (PCB) substrates have recently been developed and implemented. However, some PCB materials, such as FR4, are hydrophobic by nature. Hydrophobicity prevents aqueous solutions from entering microchannels composed of such materials, resulting in the creation of bubbles during filling. Furthermore, non-specific proteins or other biomolecules prefer hydrophobic surfaces, affecting the concentration of reagents in microfluidic devices having hydrophobic surfaces.
Fig 1. Schematic of microchannel formation on FR4 substrates.
Alfa Chemistry looked into well-known and simple-to-implement stable hydrophilization methods for FR4 substrates, such as plasma etching and PEG coating. On plasma micro- and nano-textured FR4 surfaces, we establish surface superhydrophilization with extraordinarily high stability over time at moderate and high temperatures. The hydrophilicity of the FR4 surfaces is maintained at high temperatures thanks to a temporally stable PEG-silane coating. Water contact angle measurements as a function of time following surface hydrophilization were used to assess the changed surface's wettability, while protein adsorption was evaluated in the presence of PEG coating protein rejection. Photolithography was used to create open microchannels on the PCB to test the coating's hydrophilicity.
Reference
- Cunaj E, et al. (2018). "Stable Hydrophilization of FR4 and Polyimide-Based Substrates Implemented in Microfluidics-on-PCB." Surface and Coatings Technology. 334: 292-299.
