We present a microcontact
printing (μCP) routine suitable
to introduce defined (sub-) microscale patterns on surface substrates
exhibiting a high capillary activity and receptive to a silane-based
chemistry. This is achieved by transferring functional trivalent alkoxysilanes,
such as (3-aminopropyl)-triethoxysilane (APTES) as a low-molecular
weight ink via reversible covalent attachment to polymer brushes grafted
from elastomeric polydimethylsiloxane (PDMS) stamps. The brushes consist
of poly{
N
-[tris(hydroxymethyl)-methyl]acrylamide}
(PTrisAAm) synthesized by reversible addition–fragmentation
chain-transfer (RAFT)-polymerization and used for immobilization of
the alkoxysilane-based ink by substituting the alkoxy moieties with
polymer-bound hydroxyl groups. Upon physical contact of the silane-carrying
polymers with surfaces, the conjugated silane transfers to the substrate,
thus completely suppressing ink-flow and, in turn, maximizing printing
accuracy even for otherwise not addressable substrate topographies.
We provide a concisely conducted investigation on polymer brush formation
using atomic force microscopy (AFM) and ellipsometry as well as ink
immobilization utilizing two-dimensional proton nuclear Overhauser
enhancement spectroscopy (
1
H–
1
H-NOESY-NMR).
We analyze the μCP process by printing onto Si-wafers and show
how even distinctively rough surfaces can be addressed, which otherwise
represent particularly challenging substrates.
Their inherent directional information renders patchy particles interesting building blocks for advanced applications in materials science. In this study, a feasible method to fabricate patchy silicon dioxide microspheres is demonstrated, which they are able to equip with tailor‐made polymeric materials as patches. Their fabrication method relies on a solid‐state supported microcontact printing (µCP) routine optimized for the transfer of functional groups to capillary‐active substrates, which is used to introduce amino functionalities as patches to a monolayer of particles. Acting as anchor groups for polymerization, photo‐iniferter reversible addition‐fragmentation chain‐transfer (RAFT) is used to graft polymer from the patch areas. Accordingly, particles with poly(N‐acryloyl morpholine), poly(N‐isopropyl acrylamide), and poly(n‐butyl acrylate) are prepared as representative acrylic acid‐derived functional patch materials. To facilitate their handling in water, a passivation strategy of the particles for aqueous systems is introduced. The protocol introduced here, therefore, promises a vast degree of freedom in engineering the surface properties of highly functional patchy particles. This feature is unmatched by other techniques to fabricate anisotropic colloids. The method, thus, can be considered a platform technology, culminating in the fabrication of particles that possess locally precisely formed patches on particles at a low µm scale with a high material functionality.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.