Characterization of long‐term stability of hydrophilized PEG‐grafted PDMS within different media for biotechnological and pharmaceutical applications

Abstract

Poly(dimethylsiloxane) (PDMS) is broadly utilized for the development of disposable lab-on-a-chip systems. For many microfluidic applications hydrophilic surface characteristics are indispensable. In this work, an easy, reliable and stable surface hydrophilization procedure based on poly(ethylene glycol) (PEG)-silanization is presented that overcomes the hydrophobic nature of PDMS. Furthermore, the long-term stability of the grafting as well as the effect of different parameters (e.g., applied solvent) on the hydrophilicity according to the measured contact angles (CAs) are analyzed within different media. Finally, the successful hydrophilization of different PDMS microfluidic devices and the effect of its performance are demonstrated (e.g., in a micro-emulsification component).Effect of the surface properties of PDMS-structured devices on the performance of drop emulsification with regard to the CA: (a) bare, hydrophobic and (b) PEG-grafted, hydrophilic PDMS.

Suppressing Surface Reconstruction of Superhydrophobic PDMS Using a Superhydrophilic Zwitterionic Polymer

“…Despite their ubiquitous use, PEG coatings are unstable, which has been a well-known problem for years due to reconstruction that occurs at the interface between the PDMS and PEG polymers (Figure 1c). 11, 13, 17 While PEG is often considered a hydrophilic polymer, this material is in fact amphiphilic, being soluble in such non-polar solvents such as dichloromethane and toluene, in addition to water.…”

A Versatile Star PEG Grafting Method for the Generation of Nonfouling and Nonthrombogenic Surfaces

“…While simple adsorption is flexible and convenient, its efficacy is limited by the tendency of PEG to elute off the surface [13]. Stable PEG coatings generated by direct covalent chemical coupling to substrates have already been reported [14]. However, this approach is far from being versatile since it relies on the availability of compatible functional groups on both PEG and the host surface as well as on their respective surface densities.…”

A miniaturised autonomous sensor based on nanowire materials platform: the SiNAPS mote

“…For practical applications such as in-the-field diagnostics, the most useful form of fluid delivery is via passive capillary action-obviating the need for any exterior pumping equipment to propel the analyte through the device. Passive delivery can be can be achieved in PDMS devices by careful design of the channel geometry and, most importantly, by rendering the channel surface hydrophilic using a suitable functionalization protocol [39]. For the exploratory testing carried out here, however, hydrodynamic delivery of the analyte from a syringe pump via PTFE tubing was deemed more appropriate-offering the ability to easily and repeatedly fill and empty the channel with different solutions as required.…”