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Conventional fabrication methods to obtain metal patterns on polymer substrates are restricted by high operating temperature and complex preparation steps. The present study demonstrates a simple yet versatile method for preparation of silver nanoparticle micropatterns on polymer substrates with various surface geometry. With the microworking robot technique, we were able not only to directly structure the surface, but also precisely deposit silver nanoparticle ink on the desired surface location with the minimum usage of ink material. The prepared silver nanoparticle ink, containing silver cations and polyethylene glycol (PEG) as a reducing agent, yields silver nanoparticle micropatterns on plastic substrates at low sintering temperature without any contamination. The influence of the ink behaviour was studied, such as substrate wettability, ink volume, and sintering temperature. The ultraviolet visible (UV–vis), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements revealed the formation of micropatterns with uniformly distributed silver nanoparticles. The prepared patterns are expected to have a broad range of applications in optics, medicine, and sensor devices owing to the unique properties of silver. Furthermore, the deposition of a chemical compound, which is different from the substrate material, not only adds a fourth dimension to the prestructured three-dimensional (3D) surfaces, but also opens new application areas to the conventional surface structures.

While the conventional photomask technique gives only two-dimensional anisotropies, in this study we fabricated microstructured polymer surfaces with a selective three-dimensional anisotropy. With the applied removable mesh, we were able to confine the contacting area between the surface and photoinitiator and provide three-dimensional wettability anisotropies. Different types of meshes were used depending on the desired micropatterns shape, size and substrate material. The results revealed the three-dimensional anisotropic micropits pattern with depth profiles, which would be applicable for the confinement and patterning of cells and biomolecules. In addition, the proposed method is applicable for creating selectively activated polymer surface as a substrate for further atomic layer deposition. Moreover, we demonstrate a low cost and fast mass productive method for patterning a viscous polymer liquid in a micro-sized scale.

Multiscale structured surfaces have roughness distributions at various spatial frequencies that affect surface properties of materials. A recently developed filtered power spectral density (FPSD) method for surface roughness characterization was generalized to comprise structures from micro- to nanoscale. Furthermore, a uniform analysis method for micro- and nanoscale characterization over five orders of magnitudes was found by combining optical profilometry data, at the microscale level and atomic force microscopy data, at the nanoscale level. The FPSD method was also combined with structure simulation for multiscales, thus the roughness distributions can be designed and studied without the fabrication of structures. Furthermore, the FPSD simulation offers a design tool for structure–property correlations.

Various systematically controlled, ordered and randomized micropillar structures were fabricated onto polypropylene by injection molding. Mold inserts were prepared by a micro-working robot. The advantages of this simple surface texturing application include the rigorous control of the pillar positions and the use of a variety of polymers. The textured surfaces were characterized both in horizontal and vertical directions. Power spectral density (PSD) curves combined with filtered root-mean-square (RMS) values provide structure periodicities and roughness differences between various spatial frequencies, respectively. The developed characterization tool is useful in texture mimicking when substantial periodicities and roughness is obtained and imitated in the input data of the micro-working robot. Hence, injection molded micropillar surfaces can possess similar spatial frequency and roughness features to that of mimicked surfaces. The developed characterization method was also connected to the texture design. The height profiles of structures corresponding to the fabricated surfaces were predicted from the experimental input data of the micro-working robot, and the PSD curves were generated to obtain the connection between experimental and predicted structures. The rigorous correspondence between the experimental and predicted structures and the filtered RMS values indicates that the developed design tool enables the theoretical inspection of desired structures. This can also be used in texture mimicking to expedite experimental work.

A multilayer photocatalytic TiO 2 coating on a high-density polyethylene (HDPE) disk was found to degrade aqueous methylene blue in a batch reactor study. The TiO 2 coating was fabricated by a low-temperature method using polyurethane resin (PU) as a barrier layer for HDPE and as a binding agent for two TiO 2 layers. Adequate adhesion between the HDPE substrate and PU barrier in aqueous environment was ensured with an oxygen plasma treatment. The photocatalytic effect of immersed TiO 2 coating on the degradation of methylene blue in aqueous solution was monitored by UV–vis spectrometry as a function of UV-illumination time. Samples were allowed to adsorb methylene blue in the dark for 1 h before the UV-degradation experiments were started. The percentages of methylene blue degraded during 6 h UV illumination ( λ = 365 nm) varied from 80% to 92%. The degradation followed pseudo-first order reaction kinetics, and the observed rate constants ( k obs ) were between 0.27 and 0.43 h −1 .

Cycloolefin copolymer (COC) and poly(vinyl chloride) (PVC) surfaces were patterned with nanopillars or with microbumps on which nanopillars were superimposed. The area of patterned surfaces was several square centimeters. Patterning was achieved by applying nanoporous anodized aluminum oxide (AAO) membrane as a mask in injection molding or imprinting. Nanostructures superimposed on microstructures were achieved by patterning the AAO mask with microstructures before anodization. Micro- and nanometer-sized structures could then be transferred simultaneously to polymer surfaces. Structures were characterized by SEM, AFM, and contact profilometry. The effect of different-sized structures on properties of the polymer surface was studied by contact angle measurements. Relative to the smooth surface, the increase in water contact angle on a COC surface with nanostructures superimposed on microstructures was up to 50°.

A quantitative radiochemical measuring procedure was used to investigate soil adhesion on laboratory-made polyvinyl chloride (PVC) surfaces. The materials contained different plasticizers and microstructures. Both the quality and amount of plasticizers and the microstructure affected the cleanability of the PVC samples. The surface topography and structures were examined with a contact angle meter, atomic force microscopy (AFM) and a contact profilometer.