3D Printing of Oil Paintings Based on Material Jetting and Its Reduction of Staircase Effect

Material jetting is a high-precision and fast 3D printing technique for color 3D objects reproduction, but it also suffers from color accuracy and jagged issues. The UV inks jetting processes based on the polymer jetting principle have been studied from printing materials regarding the parameters in the default layer order, which is prone to staircase effects. In this work, utilizing the Mimaki UV inks jetting system with a variable layer thickness, a new framework to print a photogrammetry-based oil painting 3D model has been proposed with the tunable coloring layer sequence to improve the jagged challenge between adjacent layers. Based on contour tracking, a height-rendering image of the oil painting model is generated, which is further segmented and pasted to the corresponding slicing layers to control the overall printing sequence of coloring layers and white layers. The final results show that photogrammetric models of oil paintings can be printed vividly by UV-curable color polymers, and that the proposed reverse-sequence printing method can significantly improve the staircase effect based on visual assessment and color difference. Finally, the case of polymer-based oil painting 3D printing provides new insights for optimizing color 3D printing processes based on other substrates and print accuracy to improve the corresponding staircase effect.

Tuning chromatic response, sensitivity, and specificity of polydiacetylene-based sensors

In this review, we provide an overview of six major techniques to tune the sensitivity and specificity of polydiacetylene-based sensors.

Glass-transition-induced color-changing resins containing layered polydiacetylene

A phase-segregated composite of polystyrene (PSt) and layered polydiacetylene (PDA) was formed through simultaneous polymerization and crystallization. As the motion of PSt chains with glass transition is transferred to that of PDA, the color change was achieved by the shortening of the conjugation length with deformation of the layered structure.

Selective Labeling and Growth Inhibition of Pseudomonas aeruginosa by Aminoguanidine Carbon Dots

Pseudomonas aeruginosa is a highly virulent bacterium, particularly associated with the spread of multidrug resistance. Here we show that carbon dots (C-dots), synthesized from aminoguanidine and citric acid precursors, can selectively stain and inhibit the growth of P. aeruginosa strains. The aminoguanidine-C-dots were shown both to target P. aeruginosa bacterial cells and also to inhibit biofilm formation by the bacteria. Mechanistic analysis points to interactions between aminoguanidine residues on the C-dots' surface and P. aeruginosa lipopolysaccharide moieties as the likely determinants for both antibacterial and labeling activities. Indeed, the application of biomimetic membrane assays reveals that LPS-promoted insertion and bilayer permeation constitute the primary factors in the anti- P. aeruginosa effect of the aminoguanidine-C-dots. The aminoguanidine C-dots are easy to prepare in large quantities and are inexpensive and biocompatible and thus may be employed as a useful vehicle for selective staining and antibacterial activity against P. aeruginosa.

A colorimetric chemosensor for heptanal with selectivity over formaldehyde and acetaldehyde through synergistic interaction of hydrophobic interactions and oxime formation

Hydroxylamine-functionalized polydiacetylene was evaluated as a heptanal chemosensor with selectivity over formaldehyde and acetaldehyde.

Real-Time Imaging of 2D and 3D Temperature Distribution: Coating of Metal-Ion-Intercalated Organic Layered Composites with Tunable Stimuli-Responsive Properties

Organic layered materials have intercalation and dynamic properties. The dynamic properties are tuned by the intercalation of the guests. In general, however, it is not easy to achieve the homogeneous and thin coating of the layered materials on substrates with complex shapes because of the two-dimensional anisotropic structures. In the present work, the layered organic composites were homogeneously coated on a variety of substrates for application to practical devices. The metal-ion-intercalated layered polydiacetylene (PDA-Mⁿ⁺) with tunable stimuli-responsive color-change properties was coated on substrates, such as paper and cotton consisting of cellulose fibers. The homogeneous and thin coating of the precursor monomer crystal was achieved on the substrates through the controlled crystal growth. The intercalation and topochemical polymerization generated PDA-Mⁿ⁺ on the substrates. The PDA-Mⁿ⁺-coated devices visualized temperature distribution of two-dimensional surface and three-dimensional space in real time.

Colorimetric Polydiacetylene-Aerogel Detector for Volatile Organic Compounds (VOCs)

A new hybrid system comprising polydiacetylene (PDA), a chromatic conjugated polymer, embedded within aerogel pores has been constructed. The PDA-aerogel powder underwent dramatic color changes in the presence of volatile organic compounds (VOCs), facilitated through infiltration of the gas molecules into the highly porous aerogel matrix and their interactions with the aerogel-embedded PDA units. The PDA-aerogel composite exhibited rapid color/fluorescence response and enhanced signals upon exposure to low VOC concentrations. Encapsulation of PDA derivatives displaying different headgroups within the aerogel produced distinct VOC-dependent color transformations, forming a PDA-aerogel "artificial nose".