Polydiacetylene Films Research Articles

Photoinduced Increase in the Conjugation Length of Polymer Chains in Blue-Phase Polydiacetylene Films based on Diacetylene Alcohol Derivatives

Photoinduced Increase in the Conjugation Length of Polymer Chains in Blue-Phase Polydiacetylene Films based on Diacetylene Alcohol Derivatives

Polydiacetylene a unique material to design biosensors

Polydiacetylene film has gained so much popularity because of its ability to transform from blue-to-red calorimetric transition as well as from non-fluorescent to fluorescent when it is exposed to different stimuli. Thus, PDA offers the easiest and the most convenient way for sensing where detection can be done using the naked eye. Accordingly, PDA has been already used to demonstrate various biosensors. In this review paper, the mechanism for detecting different microorganisms like bacteria, viruses, and a tool to detect diagnosing diseases like cancer, tumor, and various genetic diseases for their effective treatment also polydiacetylene sensors in the area of food technology are discussed.

Characterizing and Tuning the Properties of Polydiacetylene Films for Sensing Applications.

Self-assembled, polymerized diacetylene (DA) nanostructures and two-dimensional films have been studied over the past two decades for sensor applications because of their straightforward visual readout. DA monomers, when exposed to UV light, polymerize to produce a visibly blue polymer. Blue phase polydiacetylenes (PDAs) when exposed to an external stimuli, such as temperature or UV light, undergo a chromatic phase transition to a fluorescent, visibly red phase. The tunability of the monomer to blue to red chromatic phase transitions by choice of diacetylene monomer in the presence of metal cations is systematically and comprehensively investigated to determine their effects on the properties of PDA Langmuir films. The polymerization kinetics and domain morphology of the PDA films were characterized using polarized fluorescent microscopy, UV-vis-fluorescent spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Increasing the monomer alkyl tail length was found to strongly increase the UV dose necessary to produce optimally blue films and fully red films. A decrease in the polymer domain size was also correlated with longer-tailed DA molecules. Metal cations have a diverse effect on the film behavior. Alkaline-earth metals such as Mg, Ca, and Ba have a negligible effect on the phase transition kinetics but can be used to tune PDA polymer domain sizes. The Ni and Fe cations increase the UV dose necessary to produce red phase PDA films and significantly decrease the polymer domain sizes. The Zn, Cd, and Cu ions exhibit strong directed interactions with the PDA carboxylic acid headgroups, resulting in quenched fluorescence and a unique film morphology. FTIR analysis provides insight into the metal-PDA binding mechanisms and demonstrates that the coordination between the PDA film headgroups and the metal cations can be correlated with changes in the film morphology and kinetics. The findings from these studies will have broad utility for tuning PDA-based sensors for different applications and sensitivity ranges.

Near-Infrared Light-Triggered Enantioselective Photopolymerization of Polydiacetylene Films Assisted by Ag and NaYF4 Nanoparticles

Recently, near-infrared (NIR) light-triggered photochemical reactions have been of particular interest owing to their potential in solar-driven chemistry and biomedical applications. However, asymm...

Preparation and Properties of Solvent-induced Discoloration Polydiacetylene Sensors

Polydiacetylene (PDA) films were prepared from 10, 12-pentacosadiynoic acid monomers by 1, 4-addition polymerization. The PDA sensors had different discoloration properties for different solvents. With the increase of time, the appearance color of the sensor changed from blue to red. The fluorescence properties of the films were studied by fluorescence spectra. There was no fluorescence phenomenon in blue-phase PDA, but there was fluorescence phenomenon in red-phase PDA film. The fluorescence signal peak appeared at 570 nm. In addition, the PDA polyvinyl alcohol (PVA) film and PDA test paper were prepared with PVA and filter paper as substrates, and their properties were studied. The PDA test paper shows a better tendency to change color from blue to red to the solvent, and the discoloration can complete in 1 s.

Development and Evaluation of the Chromatic Behavior of an Intelligent Packaging Material Based on Cellulose Acetate Incorporated with Polydiacetylene for an Efficient Packaging.

Global growth of the food industry and the demand for new products with natural characteristics, safe conditions and traceability have driven researches for the development of technologies such as intelligent packaging, capable to fulfil those needs. Polydiacetylene (PDA) is a synthetic material that has been highlighted in research field as a sensor substance, which can be used to produce intelligent packaging capable to detect chemical or biochemical changes in foods and in their environment due to PDA’s color transition from blue to red. This work focused on the development and optimization of an intelligent packaging constituted of a polymeric matrix of cellulose acetate-based incorporated with PDA as the substance sensor. Cellulose acetate films (3% wt.) were developed by a casting method, and the amounts of triethyl citrate plasticizer (TEC) (0–25% wt. of cellulose-acetate) and PDA (0–60 mg) were analyzed to optimize the conditions for the best color transitioning at this study range. The compound amounts incorporated into polymeric matrices were established according to Central Composite Designs (CCD). Three more design variables were analyzed, such as the polymerization time of PDA under UV light exposition (0–60 min), pH values (4–11) and temperature exposure on the film (0–100 °C), important factors on the behavior of PDA’s color changing. In this study, film thickness and film color coordinates were measured in order to study the homogeneity and the color transitioning of PDA films under different pH and temperature conditions, with the purpose of maximizing the color changes through the optimization of PDA and TEC concentrations into the cellulose acetate matrix and the polymerization degree trigged by UV light irradiation. The optimal film conditions were obtained by adding 50.48 g of PDA and 10% of TEC, polymerization time of 18 min under UV light, at 100 °C ± 2 °C of temperature exposure. The changes in pH alone did not statistically influence the color coordinates measured at the analyzed ratio; however, variations in pH associated with other factors had a significant effect on visual color changes, and observations were described. PDA films were optimized to maximize color change in order to obtain a cheap and simple technology to produce intelligent packaging capable to monitor food products along the distribution chain in real time, improving the food quality control and consumer safety.

New Blue-Phase Polydiacetylenes under Prolonged UV Irradiation

Bilayer Langmuir-Schaefer films of blue-phase polydiacetylenes of three alcohol derivatives of unsymmetrical diynylic N-arylcarbamates are studied. It is found that a decrease or an increase in the number of methylene groups in the hydrophobic part of the diyne molecule by one unit followed by prolonged (to 80 min) UV irradiation of the film leads to either a gradual transformation of the blue polymer to the purple one or to a maximum increase in the conjugation length of the polymer chain of the blue polymer.

Dissymmetry enhancement in enantioselective synthesis of helical polydiacetylene by application of superchiral light

Superchiral light, generated by the interference of two counter-propagating circularly polarized light (CPL) with same frequency, opposite handedness and different intensity, exhibits enhanced dissymmetry in its interaction with chiral molecules, and has the potential for ultrasensitive detection and characterization of chiral molecules. It is anticipated that the enhanced optical dissymmetry in superchiral light (SCL) field may be utilized to promote asymmetric photochemical reactions efficiency. Herein we reported SCL impart greater chiral bias to trigger asymmetric photo-polymerization reaction from initially achiral diacetylene (DA) monomer, and the enhanced optical dissymmetry for whole polydiacetylene (PDA) films could be achieved. An explanation based on the chiral transfer and amplification of chiral bias from SCL during the polymerization process has been proposed. Moreover, thus formed chiral PDA films polymerized by SCL exhibited enhanced enantioselective recognition ability, and can serve as a direct visual probe for the discrimination of some specific enantiomers.

Chromatic detection of Cs ions using polydiacetylene-based vesicles containing crown-ether-like ethylene glycol units

Radioactive 137Cs, which have a half-life of about 30.17 years, are a major source of nuclear pollution and should be detected and removed. For this purpose, a colorimetric, polydiacetylene (PDA) vesicle-based sensor was synthesized to detect Cs ions. The polymer vesicles consisted of commonly used 10,12-pentacosadiynoic acid (PCDA) and its derivatives. One of the derivatives that contained tetraethylene glycol (TEG) units at the end of the PCDA side chain, and thus it acted as a chelating agent that surrounded the Cs ion like a crown ether. As a result, the main chain of the PDA was distorted by the chelation of TEG and Cs ions, resulting in a blue-red color change. To provide selectivity to the PDA vesicles, another derivative was incorporated to the PDA vesicles with controlled amount, which was not responsive to alkali metal ions. The changes in the colorimetric response of the vesicles were not observed in the presence of other alkali metal ions such as Na, K, and Rb ions, indicating that the TEG units fitted well in size with the ionic radius of the Cs ion, resulting in high selectivity. Solid-state PDA film was also fabricated to provide selective detection of Cs ions.

Graphene photodetector with polydiacetylenes acting as both transfer-supporting and light-absorbing layers: Flexible, broadband, ultrahigh photoresponsivity and detectivity

Polydiacetylene (PDA) films are shown enabling the combination of graphene transfer and photodetector fabrication into one step. Under the assistance of PDA, centimeter pieces of graphene can be acquired with free of broken or fractures. The constructed PDA/graphene hybrid films demonstrate ultrahigh, gate-tunable responsivity (R) and detectivity (D*) from UV to visible wavelengths, for instance, statistical R and D* at 320 nm achieves 556 A W−1 and 6.0*1011 Jones at the irradiance of 0.24 mW cm−2, indicating their superior broadband and sensitive detecting abilities. Kinetic response of our devices is not fast as the cost of high responsivity, which, however, can be efficiently amended by applying potential pulses through back gate electrodes. If supported PDA/graphene films on polymer substrate, the devices can still work reliably after being bended 25,000 cycles, and even can respond to light stimulus evidently at a heavily-stretched state created by a completely-folded human finger, revealing their remarkable flexibilities. The developed strategy of killing two birds (graphene transfer and functionalization) with one stone (PDA films) is highly desirable for developing graphene devices. And, the constructed ultrasensitive PDA/graphene photodetectors have considerable opportunities to be used in assorted photosensing areas that may not have critical requirement on operating speed.

A skin-like stretchable colorimetric temperature sensor

Wearable and stretchable physical sensors that can conformally contact on the surface of organs or skin provide a new opportunity for human-activity monitoring and personal healthcare. Particularly, various attempts have been made in exploiting wearable and conformal sensors for thermal characterization of human skin. In this respect, skin-mounted thermochromic films show great capabilities in body temperature sensing. Thermochromic temperature sensors are attractive because of their easy signal analysis and optical recording, such as color transition and fluorescence emission change upon thermal stimuli. Here, desirable mechanical properties that match epidermis are obtained by physical crosslinking of polydiacetylene (PDA) and transparent elastomeric polydimethylsiloxane (PDMS) networks. The resulting PDA film displayed thermochromic and thermofluorescent transition temperature in the range of 25–85°C, with stretchability up to 300% and a skin-like Young’s modulus of ~230 kPa. This easy signal-handling provides excellent references for further design of convenient noninvasive sensing systems.

Polydiacetylene (PDA) Film: A unique sensing element

Polydiacetylene (PDA) Langmuir films consist in two structural and chromic phases: metastable, non-fluorescent blue phase and stable, auto-fluorescent red phase. They are promising material for developing sensor with their fluorescence/colorimetric dual response. The blue PDA film when exposed to analyte of interest, shows a chromatic change to red phase, is utilised to detect sensor array. PDA molecules form a stable trilayer on maximum compression and after UV polymerization they are transferred to solid substrate.

Good conductivity of a single component polydiacetylene film

Two films were prepared from single component monomer solutions. In these monomers, diacetylene and two acid groups are licked by flexible side chains. The side chain serves as the spacer between diacetylenes. After UV-irradiation, monomer films were transformed to polydiacetylene films and one of films exhibited conductivity drastically increases. This conductivity is two orders of magnitude greater than the conductivity value of reported nondoped polydiacetylene films.

Light-Induced Conductivity in a Solution-Processed Film of Polydiacetylene and Perylene Diimide.

We prepared a solution-processed film comprising a drop-casted mixture of melamine-diacetylene and perylene bis(dicarboximide) (PDI). We show that the diacetylene monomers adopt distinct crystalline organization in the presence of the PDI residues. Importantly, the drop-casted diacetylene/PDI film exhibits ultraviolet light-induced conductivity, ascribed to effective transport of charge carriers in the conjugated polymerized network.

Preparation of Chiral Polydiacetylene Films by Using Three-Photon Polymerization.

Asymmetric polymerization of polydiacetylene (PDA) from commercially available achiral derivative of diacetylene monomer using circularly polarized pulse laser is demonstrated. Chiral source was only circularly polarized laser, and irradiation of left- and right-circularly polarized light effectively promoted the polymerization of chiral PDAs with opposite handedness. Difference between the laser wavelength and the absorption peak of monomer suggested the contribution of the multiphoton excitation to the photo-polymerization. Laser power dependence of the polymerization rate indicated the possibility of three-photon polymerization.

Colorimetric analysis of painting materials using polymer-supported polydiacetylene films

Polydiacetylenes, exhibiting different headgroups, distinguish among different painting materials.

Chromatic reversibility of multilayered polydiacetylene cast film

The cast film of polydiacetylene and PVA on a glass surface was fabricated to demonstrate a very fast and reversible chromatic response with respect to change in temperature. The N-[2-(2-hydroxyethoxy)ethyl]pentacosa-10,12-diynamide was sonicated in PVA solution. This solution was dried at room temperature for 3 days and the cast film was formed as multilayered structure. The UV irradiation led to in situ polymerization. The layered structures were confirmed by XRD data. The regularly layered polymeric cast film showed a very fast and reversible transition from blue to red. These results would be attributed to the well-arranged multilayer structure and hydrogen bonding.

Poly(methyl methacrylate)-supported polydiacetylene films: unique chromatic transitions and molecular sensing.

Polydiacetylenes (PDAs) constitute a family of conjugated polymers exhibiting unique colorimetric and fluorescence transitions, and have attracted significant interest as chemo- and biosensing materials. We spin-coated PDA films upon poly(methyl methacrylate) (PMMA), and investigated the photophysical properties and sensing applications of the new PDA configuration. Specifically, the as-polymerized blue PDA layer underwent distinct transformations to purple, red, and yellow phases, which could be quantified through conventional color scanning combined with application of image analysis algorithms. Furthermore, we recorded a reversible red-purple PDA transition that was induced by ultraviolet irradiation, a phenomenon that had not been reported previously in PDA film systems. We show that distinct color and fluorescence transitions were induced in the PMMA-supported PDA films by amphiphilic substances-surfactants and ionic liquids-and that the chromatic transformations were correlated to the analyte structures and properties. Overall, this study presents a new chromatic PDA film system in which noncovalent interactions between the PMMA substrate and spin-coated PDA give rise to distinct chromatic properties and molecular sensing capabilities.

The effect of perfluorotetradecanoic acid on the structure of photopolymerized 10,12-pentacosadiynoic acid films at the air–water interface

The influence of the perfluorinated fatty acid perfluorotetradecanoic acid (CF3(CF2)12COOH; PF) on the structure of films of the photopolymerizable surfactant 10,12-pentacosadiynoic acid (PCDA) has been explored at the air–water interface through a combination of surface pressure–area compression measurements and Brewster angle microscopy imaging during the time course of UV photopolymerization. The addition of the perfluorocarbon to PCDA results in a film structure that differs significantly from the pure PCDA alone, with the most pronounced difference being the formation of photopolymer strands oriented perpendicular to the direction of film compression in a Langmuir trough. Film compression data, supported by in situ fluorescence spectrophotometry and atomic force microscope images of deposited films, suggest that compression-induced stress and accompanying film buckling, enhanced by the strong cohesion between PF and PCDA, contributes to the observed structural differences between the mixed PF–PCDA and pure PCDA photopolymerized films. This approach to forming patterned polydiacetylene films is discussed in comparison with other demonstrated methods for structuring this technologically important polymer.

Twinning and Phase Control in Template-Directed ZnS and (Cd,Zn)S Nanocrystals

We report on the nucleation and growth of ZnS and (CdxZn1–x)S nanocrystals on polydiacetylene Langmuir films. It was found that the 3–5 nm nanocrystals form ordered linear arrays aligned at a constant 27° angle with respect to the conjugated direction of the polydiacetylene film, as derived from the optimal alignment between the two phases. ZnS nanocrystals were found to nucleate specifically from the zinc blende (001) face. Because of closely matched interfacial relations, twinning defects were induced on the {111} planes. These nanometer-sized twin crystals exhibit extra {111} electron diffraction reflections due to elongation of reciprocal space spots, despite their off axis orientation. The composition of solid solution (Cd,Zn)S nanocrystals depends on the Zn2+\Cd2+ ratio in the aqueous subphase. Their structure is affected by the template mismatch both by twinning, as is the case for ZnS, for which continuous compositional shift is observed, and by phase shift to hexagonal wurtzite, with a pure CdS composition. The nanocrystals exhibited a continuous energy-gap shift, reflecting the Zn/Cd ratio in the solid solution. We demonstrate control over the nanocrystals’ crystal structure, defect structure, orientation, and composition, providing a potentially effective tool for band-gap engineering in organic–inorganic hybrid assemblies.