Fully Printed Flexible Humidity Sensor

AbstractA humidity sensor that employs interdigitated capacitors (IDC) printed with silver (Ag) nanoparticle based ink on a flexible poly ethylene terephthalate (PET) substrate was successfully fabricated using gravure printing process. Thicknesses of 1μm and 500μm of a humidity sensitive polymer poly (2-hydroxyethyl methacrylate) (pHEMA) was deposited on the IDCs by means of gravure printing. The capacitive response of the sensor towards relative humidity (RH) was measured in the range of 30% RH to 80% RH; the maximum percentage change in capacitance was 172% at 80% RH when compared to base capacitance at 30% RH. The humidity response of the printed sensor revealed a very high stability with a maximum error of 0.6% and 0.8% from the average value at 40% RH and 60% RH, respectively

Chemo-biocatalytic one-pot two-step conversion of cyclic amine to lactam using whole cell monoamine oxidase

BACKGROUND: Most biocatalysts currently involved in one‐pot chemoenzymatic cascades are pure enzymes, while whole cells and crude enzyme extracts remain unexplored. This work aims to develop a chemo‐biocatalytic one‐pot two‐step system involving whole cell monoamine oxidase (MAO, EC 1.4.3.4) coupled with a Cu‐based oxidative system (CuI/H2O2) for the transformation of 1,2,3,4‐tetrahydroisoquinoline (THIQ) to 3,4‐dihydroisoquinolin‐1(2H)‐one (DHIO). RESULTS: MAO‐N variants D9 and D11 were tested as whole cell and crude lysate biocatalysts for biological oxidation. Whole Escherichia coli OverExpress C43(DE3) cells expressing MAO‐N D9 showed the best performance (Vmax = 36.58 mmol L−1 h−1, KM = 8.124 mmol L−1, maximum specific productivity 89.3 μmol min−1 g−1DCW) and were employed in combination with CuI/H2O2 in a sequential one‐pot two‐step process. The biotransformation was scaled‐up to the initial volume of 25 mL and after triple THIQ feeding, 48.2 mmol L−1 of the intermediate 3,4‐dihydroisoquinoline (DHIQ) was obtained with a yield of 71.3%. Afterwards, chemical catalysts (1 mol% CuI and 10 eq. H2O2) were added to the biologically produced DHIQ, which was transformed to ∼30 mmol L−1 DHIO at 69.4% overall yield. CONCLUSION: As MAO‐N variants have wide substrate specificity, this work broadens the portfolio of one‐pot chemoenzymatic processes employing whole cell biocatalysts, representing an alternative to using pure enzymes

Surface Treatments for Inkjet Printing onto a PTFE-Based Substrate for High Frequency Applications

This document is the Accepted Manuscript version of a Published Work that appeared in final form in the journal Industrial and Engineering Chemistry Research [copyright © American Chemical Society] after peer review and technical editing by the publisher. To access the final edited and published work see: http://pubs.acs.org/doi/abs/10.1021/ie4006639Inkjet printing onto laminates for use in high frequency applications (high frequency laminates) is challenging, due to the substrate surface roughness present after etching away the copper layer(s). This has a detrimental effect on interconnect losses as the frequency increases. In this paper, different surface treatments to reduce the surface roughness of a typical high frequency laminate (RO3006) are investigated. In particular, the importance of matching the substrate surface energy to the ink to achieve a smooth coated layer for the case of a UV cured insulator is demonstrated. This is achievable within the parameters of heating the platen, which is a more flexible approach compared to modifying the ink to improve the ink-substrate interaction. In printing onto the surface modified substrates, the substrate roughness was observed to affect the printed line width significantly. A surface roughness factor was introduced to take into account the phenomenon by modifying the original formula of Smith et al. Lastly, the authors show that the printed line widths are also influenced by the surface tension arising from charges present on the surface modified substrates