Maurice Schmette

We present a method for the direct micropatterning of cellulose thin films using microcontact printing (µCP). This method employs a polymer brush-functionalized stamp bearing reactive imidazole groups that enable the temporary immobilization of carboxylic acids used as ink molecules in the process. During printing, the brush stamp is brought into contact with the cellulose substrate, facilitating the transfer of the ink to the surface where they bind as esters. Since the ink remains fixed either on the stamp or on the substrate, diffusive smearing is avoided, enabling high-resolution patterning down to the low micrometre scale. This capability opens avenues for the fabrication of functional papers, chemically patterned on the (sub-) microscale.

We developed a method for fabricating anisotropic monodisperse silicon dioxide (SiO2) patchy microspheres. The protocol utilizes a modified microcontact printing (µCP) technique, employing a polydimethylsiloxane (PDMS) elastomer with a regularly grooved surface topography as a stamp. The stamp’s microscale channels create a confined environment for the SiO2 microspheres, as they match the particle dimensions (~4 µm). Our solid-phase µCP routine allows for the transfer of functional trialkoxysilanes from the elastomer stamp to the particles exclusively at their contact faces. By applying a second stamp to the exposed side of the particles, a fourth patch with different chemical information is added. This fabrication process, compatible with various follow-up chemistries, adds patches with adjustable characteristics. The method is suitable to fabricate particles possessing a C4v and C2v symmetry. Importantly, the protocol is easily adaptable to other particle dimensions and surface chemistries, indicating significant potential in the field of anisotropically functionalized spherical colloidal particles.