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Injection moulding is a proven technology for high-throughput production of nanostructures, but replication of raised structures is a considerable challenge, due to the complexities of cavity filling. We have developed a platform to systematically study the effects of nanostructures with aspect ratios up to 1.2:1. A master template containing nanostructures with a continuous variation in height is produced by a novel fabrication approach using a plasma polymerized hexane layer, deposited with a thickness gradient, as a sacrificial etch mask. Results show that a careful choice of process parameters can control the stretching of nanopillar replica dimensions, allowing a variety of final pattern heights using a single master.

It is emerging that nanotopographical information can be used to induce osteogenesis from mesenchymal stromal cells from the bone marrow, and it is hoped that this nanoscale bioactivity can be utilized to engineer next generation implants. However, the osteogenic mechanism of surfaces is currently poorly understood. In this report, we investigate mechanism and implicate bone morphogenic protein (BMP) in up-regulation of RUNX2 and show that RUNX2 and its regulatory miRNAs are BMP sensitive. Our data demonstrate that osteogenic nanotopography promotes colocalization of integrins and BMP2 receptors in order to enhance osteogenic activity and that vitronectin is important in this interface. This provides insight that topographical regulation of adhesion can have effects on signaling cascades outside of cytoskeletal signaling and that adhesions can have roles in augmenting BMP signaling.

We demonstrate that engineered artificial gold chiral nanostructures display significant levels of non-linear optical activity even without plasmonic enhancement. Our work suggests that although plasmonic excitation enhances the intensity of second harmonic emission it is not a prerequisite for significant non-linear (second harmonic) optical activity. It is also shown that the non-linear optical activities of both the chiral nanostructures and simple chiral molecules on surfaces have a common origin, namely pure electric dipole excitation. This is a surprising observation given the significant difference in length scales, three orders of magnitude, between the nanostructures and simple chiral molecules. Intuitively, given that the dimensions of the nanostructures are comparable to the wavelength of visible light, one would expect non-localised higher multipole excitation (e.g. electric quadrupole and magnetic dipole) to make the dominant contribution to non-linear optical activity. The study provides experimental evidence that the electric dipole origin of non-linear optical activity is a generic phenomenon which is not limited to sub-wavelength molecules and assemblies. Our work suggests that viewing non-plasmonic nanostructures as “meta-molecules” could be useful for rationally designing substrates for optimal non-linear optical activity.

The hydrophilicity, hydrophobicity, and sliding behaviour of water droplets on nanoasperities of controlled dimensions were investigated experimentally. We show that the "hemi-wicking"theory for hydrophilic SiO2 samples successfully predicts the experimental advancing angles and that the same patterns, after silanization, become superhydrophobic in agreement with the Cassie-Baxter and Wenzel theories. Our model tophographies have the same dimensional scale of some naturally occurring structures that exhibit similar wetting properties. Our results confirm that a forest of hydrophilic/hydrophobic slender pillars is the most effective superwettable/water-repellent configuration. It is shown that the shape and curvature of the edges of the aspertieis play an important role in determining the advancing angles.

Thin diblock copolymer film have been investigated by x-ray and neutron reflectivity as well as small angle x-ray and neutron scattering. Two model systems have been investigated. PS-PDMS (25 kg/mol-25 kg/mol), which has a glass transition temperature ofca. 100 deg.C for the PS-block. This means that the structure can be frozen below that temperature, thus the development of the lamella structure may be follow by reflectivity. It was, however, not possible to reach the expected equilibrium structure. Hence the second model system, deuterateted PEP-PDMS (4.4 kg/mol-4.4 kg/mol) was chosen for its low glass transition temperature -56 deg.C. This means that the system spontaneously should form lammela ordered structures at room temperature. This orderingwas studied by neutron reflectivity and small angle neutron scattering in the temperature range from -140 deg.C(below PDMS’ glass transition temperature, -127 deg.C) and up to 250 deg.C (above the order-disorder temperature, 165 deg.C). Results werefound to be in perfect agreement with theory. Surface morphology as function of temperature was also measured, and holes in the surface resembled the periodicity measured by reflectivity. Thin diblock copolymer lm have been investigated by x-ray and neutron reflectivity as well as small angle x-ray and neutron scattering. Two model systems have been investigated. PS-PDMS (25 kg/mol-25 kg/mol), which has a glass transition temperature of ca. 100°Cfor the PS-block. This means that the structure can be frozen below that temperature, thus the development of the lamella structure may be follow by reflectivity. It was, however, not possible to reach the expected equilibrium structure. Hence the second model system, deuterateted PEP-PDMS (4.4 kg/mol-4.4 kg/mol) was chosen for its low glass transition temperature -56°C. This means that the system spontaneously should form lammela ordered structures at room temperature. This ordering was studied by neutron reflectivity and small angle neutron scattering in the temperature range from -140°C(below PDMS' glass transition temperature, -127°C) and up to 250°C(above the order-disorder temperature, 165°C). Results were found to be in perfect agreement with theory. Surface morphology as function of temperature was also measured, and holes in the surface resembled the periodicity measured by reflectivity.