PMMA Polymer Film Research Articles

Glow discharge plasma stabilization of azo dye on PMMA polymer

The effects of argon gas glow discharge plasma on the surface of DR1 dye-loaded PMMA polymer films are examined in this work. Plasma immobilizes the dye on the surface of polymer without using stabilizers. Argon plasma activates the surface through breaking some bonds and generation of radical sites. It affects the acrylate groups of PMMA leading to covalent bonds between dye and surface of polymer. In addition, plasma treatment and contact with ambient air may result in the creation of new polar components, such as carbonyl and carboxyl compounds and links that enhance the dye attachment to the polymer matrix. Besides, the dye adsorption on the polymer film is impacted by changes in surface topography. Furthermore, plasma modifies the dye conformation, which affects the adherence of the dye to the polymer surface through bringing the dye to the higher energy state. The chemical and topographical modification of dye-loaded PMMA films by plasma are investigated by spectroscopic and AFM methods. Furthermore, aging process was used to confirm dye retention on the polymer film after plasma modification as opposed to dye-loaded polymer film that was left untreated as a reference sample. Finally, investigated method suggests a novel and very affordable technique for fabrication of poly(MMA-co-DR1) copolymer in the form of a homogeneous surface layer.

Preparation and photoluminescent behaviors of bipyrimidine bridged dinuclear Eu (III) complexes and their PMMA polymer films

Four bipyrimidine bridged dinuclear Eu (III) complexes of fluorinated β-diketones were synthesized and their photoluminescence behaviors in solution, solid powder state and poly(methylmethacrylate) (PMMA) films were investigated in detail. The results showed that Eu (III) complexes and their PMMA polymer films all exhibited strong characteristic emissions of the corresponding Eu (III) ion and highly monochromatic red emissions. According to the emission spectra and luminescence decay curves, the Judd−Ofelt intensity parameters (Ω2, Ω4), lifetime (τ) and quantum efficiency were calculated. Their high Ω2 values suggested that the Eu (III) ion was in a highly polarizable ligand field in these complexes. Meanwhile the proposed energy transfer mechanisms of these complexes were also investigated and analyzed. In their PMMA polymer films, the luminescent lifetimes, quantum efficiencies were increased significantly as compared to their precursor Eu (III) complexes. Especially, the PMMA@Eu2(TMPD)6⋅Bpm polymer film displayed the longest lifetime (τ = 0.946 ms) and highest quantum efficiency (ΦLn = 71.9%). These results suggested that photoluminescence behaviors of dinuclear Eu (III) complexes doped in PMMA polymer films had been improved remarkably.

Investigation of morphology and transport properties of Na+ ion conducting PMMA:PEO hybrid polymer electrolyte

Abstract The aim of this research work is to examine the modification of structure, morphology and conductivity properties of PMMA: PEO blend hybrid polymer electrolyte system complexed with NaClO4 salt. Solution-cast procedure was adopted in preparation of these films. These films were characterized with XRD, SEM, DSC, and DC conductivity for the evaluation of modified properties. Peaks have disappeared and broadened in the XRD pattern of PMMA for higher concentration of PEO polymer and salt presented films, which indicated that attaining of higher amorphous phase in these polymer electrolyte films. Almost smooth surface morphology with fewer pores was observed in 20 wt. % of PEO and NaClO4 salt present PMMA films of SEM image. This establishes a dominant presence of amorphous content in these NaClO4 complexed PMMA:PEO hybrid electrolyte films when compared to pure PMMA and PEO. Disappearance of melting temperature was observed in all concentrations of NaClO4 salt and PEO polymer added PMMA polymer films, which suggests a decrease of crystalline and an increase of amorphous nature. Enhancing of DC conductivity with temperature was observed in all the films but higher conductivity was exhibited at higher concentration of NaClO4 salt present films.

Investigation of Dc-Conductivity and Morphology of PMMA/PANI Composite

Various inorganic acid doped PMMA/PANI composite are prepared by in-situ polymerization technique. Morphology, room temperature (RT) conductivity and DC-conductivity with temperature variation (77-300 K) are analyzed by scanning electron microscopy (SEM) and linear four probe technique, respectively. Fibril structures with different diameter are observed in doped PMMA/PANI composite, whereas smooth texture is found in PMMA polymer film. Room temperature DC conductivity is found 0.1497 × 10-2 S/cm for H2SO4-and 0.309 × 10-3 S/cm for H3PO4-, 0.244 × 10-3S/cm for HCl-doped conductive composite, respectively. Temperature dependent DC Conductivity is measured and it behaves like semiconductor.

Synthesis and Surface Characterization of PMMA Polymer Films in Pure Oxygen, Argon, and Nitrogen Glow Discharge Plasma

The anticorrosion effect and biocompatibility property of Poly (methyl methacrylate) (PMMA) materials have been used in a variety of commercially available products and medical devices for many years. In this work, the treatment of surfaces prepared PMMA films by oxygen, argon and nitrogen plasma, requires understanding the effect of low energy ions on the surface modification of the film of PMMA. Due to this, the samples of prepared PMMA were exposed to three different gases at the same discharge conditions. Changes within the morphology and surface hydrophilicity of the treated samples were characterized by optical microscope images and the measurements of contact angle. Treatment of PMMA with O2, N2, Ar gases displayed a decreasing in the contact angle that results in increasing surface free energy. Oxygen –plasma treatment of PMMA films leads to high aspect ratio topography, with increased roughness for (5-30) minute process durations.

Synthesis and photophysical properties of ditrifluoroacetoxyboron complexes with curcumin analogues

A new class of ditrifluoroacetoxyboron complexes were designed and synthesized by chelation reaction of curcumins with boron trifluoroacetate. Their photophysical behaviors were studied in different solvents, powder state and PMMA polymer films. The results indicated that these complexes revealed a green to yellow emission at 486–595 nm in solution or PMMA films and an orange to red emission at 598–710 nm in powder state. Especially, complex 2c displayed the strongest emission intensity, the highest quantum yield in solution and the longest fluorescence lifetime in powder state in these complexes. In addtion, the emission bathochromic shifts of these complexes as a function of the solvent polarity parameter ET(30) were investigated by Lippert–Mataga approximation. It was observed that these complexes exhibited the higher values of the dipole moment difference (Δμ) between the ground and excited states, which implied an intense intramolecular charge transfer characteristics and a noticeable emission solvatochromic effect.

Nonlinear optical properties of colloidal CdSe/ZnS quantum dots in PMMA

The colloidal CdSe/ZnS quantum dots (QDs) in the PMMA polymer film with different QDs concentrations were fabricated. The influence of QDs concentration and excitation pump energy on nonlinear optical (NLO) properties of PMMA capped CdSe/ZnS QDs was investigated by the Z-scan technique with nanosecond laser pulses in the near-infrared spectral band. A large effective nonlinear absorption coefficient (βeff ∼ −10−13 esu) due to the saturable absorption was observed. It was found that the appropriate concentration could lead to the reinforcement of NLO effect. In addition, the impact of the excitation energy on the nonlinear refractive index n2, real and imaginary parts of the third-order nonlinear optical susceptibility was also performed. This study involving the light–matter interactions in the colloidal quantum dots will benefit potential NLO-based applications of optoelectronics, optical modulation and photonics.

Superhydrophobic polymeric films with hierarchical structures produced by nanoimprint (NIL) and plasma roughening

The structuration of various polymeric films has been studied to create superhydrophobic surfaces. Nanoimprint lithography and/or plasma etching processes with CF4/Ar have been used on FEP, PMMA and PET polymer films. On the one hand, the effect of the CF4/Ar gases, the input power and the plasma treatment duration have been investigated in terms of etching and fluorination degree, and XPS analyses are precisely discussed. On the other hand, wettability performances were characterized. Relationships between the contact angle, the contact angle hysteresis and the surface structures have been investigated. The wetting behaviors and the transition between the Wenzel and the Cassie-Baxter states was discussed as a function of the roughness. We have prepared each studied polymer films in transparent and flexible superhydrophobic surfaces whose contact angle are ∼160° and hysteresis are ∼2°. A short plasma treatment time (10 s) is sufficient to obtain a superhydrophobic behavior on FEP and PMMA. Results indicate that hierarchical structures allow a more stable superhydrophobic state regarding inhomogeneities. Moreover, the use of plasma etching is suggested to overcome some limitations of the NIL in the case of structures with a high aspect ratio. Finally, a quick and large surface fabrication method for superhydrophobic films is detailed.

Third - Order Nonlinear Optical Properties and Optical Limiting Behavior of Celestin Blue B Dye Doped Polymer Films

Pure Poly (methylmethacrylate) (PMMA) polymer film and Celestin Blue B dye doped polymer films at different concentrations were prepared using casting technique. UV - Vis spectra were recorded to characterize the optical properties of the Celestin Blue B dye doped PMMA polymer films. The magnitudes of both real and imaginary parts of third - order nonlinear susceptibility (χ (3)) of Celestin Blue B dye doped polymer films were determined using the z - scan technique with a continuous wave laser beam at wavelength 532 nm. The nonlinear refractive index (n2) and the nonlinear absorption coefficient (β) of the Celestin Blue B dye doped polymer films were calculated. It was found that the prepared films exhibited saturable absorption (SA) and self - defocusing effect. The optical power limiting behavior also investigated for Celestin Blue B dye doped PMMA polymer films at different concentrations and the optical power limiting threshold values were determined. Results indicate that the Celestin Blue B dye doped PMMA polymer film is a promising material for future photonic device applications.

Investigation of Optical Properties of Solochrome Dark Blue Dye Doped Polymer Films

The optical properties of the pure poly(methylmethcrylate) (PMMA) polymer film and PMMA polymer films doped with Solochrome Dark Blue dye at different concentrations were investigated. The films were prepared using the casting technique. The optical absorption and transmission spectra of these films were recorded in the wavelength range 300 - 900 nm for different concentrations using UV-Vis double - beam spectrophotometer. The optical parameters of the Solochrome Dark Blue dye - doped polymer films, reflectance (R), absorption coefficient (α), extinction coefficient (κ), refractive index (n), optical and electrical conductivities (σopt and σelect), and optical energy band gap (Eg), were calculated. The effect of the dye concentration on these parameters was studied. The obtained results show that the Solochrome Dark Blue dye is a promising material for applications in photonic and optoelectronic devices.

Photochrome-doped organic films for photonic keypad locks and multi-state fluorescence.

The spectroscopic properties of poly(methyl methacrylate) polymer films doped with two kinds of photochromic molecular switches are investigated. A green-fluorescent sulfonyl diarylethene (P1) is combined with either a non-fluorescent diarylethene (P2) or red-fluorescent spiropyran (P3). Photoswitching between the colorless and colored isomers (P1: o-BTFO4 ↔ c-BTFO4, P2: o-DTE ↔ c-DTE, P3: SP ↔ MC) enables the P1 + P2 and P1 + P3 films to be cycled through three distinct states. From the initial state (o-BTFO4 + o-DTE/SP), irradiation with UV light generates the second state (c-BTFO4 + c-DTE/MC), where c-BTFO4 → c-DTE/MC energy transfer is established. Irradiation with green light then generates the third state (c-BTFO4 + o-DTE/SP), where the energy transfer acceptor is no longer present. Finally, irradiation with blue light regenerates the initial state. For the P1 + P2 film, only one state is fluorescent, with the irradiation inputs required to be entered in the correct order to access this state, acting as a keypad lock. For the P1 + P3 film, the states emit either no fluorescence, red fluorescence, or green fluorescence, all using a common excitation wavelength. Additionally, once the fluorescence is activated with UV light, it undergoes a time-dependent color transition from red to green, due to the pairing of P-type and T-type photochromes. These multi-photochromic systems may be useful for security ink or imaging applications.

Phototransparent properties in PMMA/SI(111) nanointerfaces

In this work, we report on the synthesis and non-linear optical studies of PMMA polymer films deposited on Si〈111〉 wafers by using the spin-coating method. The transport features were measured using a four-probe method. The excitation was provided by 10ns pulses of λ=1.32μm YAG: Nd laser. The photoinduced laser light was polarized by a rotating Fresnel polarizer, and the output light powers were detected using a fast response photomultiplier. At low voltages, the photoinduced dependence of optical constants does not show an essential change with respect to the photoinduced power. The effect exists only on the nano-interfaces occurring on the borders. Drastic changes are observed only at higher voltages (about 6V), which correlates with a drastic increase of the current. A novel mechanism describing low dc-elecric field for the trapping current by tunneling is proposed.

Photoluminescent PMMA polymer films doped with Eu3+-β-diketonate crown ether complex

Photograph of PMMA/PEG blend film doped with 1% [Eu(tta) 3 (DB18C6) 2 (H 2 O) 2 ] complex exhibiting red emission under UV irradiation at 366 nm. ► Effective interaction between the Eu 3+ -complex and the polymer matrix are observed. ► The luminescent films are homogeneous and preserve the polymer aspects. ► Emission quantum efficiency for the Eu 3+ -doped polymer films increased significantly. ► PMMA provides efficient luminescence co-sensitization of the Eu 3+ luminescent centers. In this work it is reported the photoluminescence sensitization effect of the bis(dibenzo-18-crown-6)diaquatris(thenoyltrifluoroacetonate)europium(III) compound, [Eu(tta) 3 (DB18C6) 2 (H 2 O) 2 ], doped into a blend of poly(methylmethacrylate) (PMMA) and polyethylene glycol (PEG) in film form. The TGA results indicate that the Eu 3+ -complex precursor is immobilized in the polymer matrix by the interaction between the Eu 3+ complex and the oxygen atoms of the PMMA polymer. The thermal behavior of these luminescent systems is similar to that of the undoped polymer. The emission spectra of the Eu 3+ -complex in the PMMA/PEG blends recorded at room temperature exhibit the characteristic bands arising from the 5 D 0 → 7 F J ( J = 0–4) intraconfigurational transitions. The emission quantum efficiency of the Eu 3+ ion doped films increased significantly, indicating an effective interaction between the Eu 3+ -complex and the polymer matrix, and both the substitution of water molecules in the first coordination sphere and an efficient luminescence co-sensitization of the Eu 3+ luminescent centers.

Synthesis of tricyanofuran chromophore with flexible rigid isolated group and its application as nonlinear optical materials

Novel organic second-order nonlinear optical (NLO) chromophore with a large flexible rigid isolated group was prepared. The NLO properties were measured in solution and PMMA polymer films. The first order hyperpolarizabilities were equal to 4×10−28esu and 7×10−29esu at 1064nm Nd:YAG laser wavelength in solvent and polymer, respectively and these results are in agreement with quantum chemical calculations. Moreover, this chromophore has high thermal stability when thermal decomposition temperature is 270°C. Electrostatic interactions of the chromophores were effectively reduced by isolated group. No apparent change of the shape of UV absorption spectra versus concentration was found.

Energy Transfer Pathways in a Rylene‐Based Triad

Herein, a study on the excitation energy migration is reported for a newly synthesized Triad with a well-defined architecture consisting of a central terrylenediimide decorated with four perylenediimide and sixteen naphthalenemonoimide chromophores. Steady-state femto- and picosecond time-resolved spectroscopy were employed to unveil the excited states dynamics in solution. Compared with the results obtained from the corresponding model compounds, the Triad is an efficient light collector over the entire visible spectral range and the fluorescence occurs mostly from the core with a quantum yield as high as 60%. The results suggest that selective excitation of the naphthalenemonoimide chromophores results in an efficient energy transfer that occurs in a cascade fashion (through the perylenediimide chromophores) towards the terrylenediimide core with time constants of <200 fs and 3.7 ps. Naphthalenemonoimide chromophores can also transfer their excitation energy to the terrylenediimide core directly via two parallel pathways with time constants of 1.5 and 8.4 ps, respectively. Additionally, single-molecule confocal microscopy experiments revealed strong emission from the terrylenediimide unit upon excitation of the naphthalenemonoimide chromophores. As time evolved, stepwise photobleaching of the multichromophoric Triad single molecules embedded in a PMMA polymer film was observed, resulting in a 96 percent probability of observing perylenediimide emission before final photobleaching under ambient conditions, substantiating the cascade energy transfer pathway. Under nitrogen atmosphere however, no perylenediimide emission could be observed for single Triad molecules embedded in a PMMA polymer film, likely as a result of the prolonged photostability of the terrylenediimide core in absence of oxygen.

Time-resolved fluorescence study on the photomerocyanine form of spiropyran and its derivative with azobenzene

The excited state dynamics of the photomerocyanine (PMC) form originating from spirobenzopyran and the bi-functional photochromic compound spirobenzopyran–azobenzene (SpAz), containing typical photochromic molecules of spirobenzopyran (Sp) and azobenzene (Az), were investigated using picosecond time-resolved fluorescence measurements in solution at 200 and 285 K and in a PMMA polymer film at 298 K. While the fluorescence lifetimes of PMC were about twice as long as those of SpAz under all experimental conditions, both lifetimes showed similar strong dependence on viscosity rather than temperature. These results suggest that non-radiative decay to an intermediate state could be accompanied by a significant conformational change. The effect of the Az moiety in this relaxation process is also discussed. It is unlikely that an energy transfer from the PMC moiety to the Az moiety occurs. It was concluded that the PMC moiety in the bi-functional SpAz is independent from the Az moiety.

Photoisomerization Processes of Azobenzene Compounds in Thin Poymer Films

Photoisomerization Processes of Azobenzene Compounds in Thin Poymer FilmsOne of the most important properties of the molecular switches is turning of a molecule by external action, e.g. by irradiation with light of definite wavelength. The molecules of promise for the molecular switches are those with azobenzene moiety. When azobenzene is irradiated with light of definite wavelength, it is possible to observe the process of trans/cis isomerisation. In this work, the influence of photoisomerisation processes on the changes in the surface potential of a novel azobenzene compound is investigated.We have studied the surface potential of a PMMA polymer film with polar azobenzene derivative of different concentrations. To orient azobenzene molecules in the film the corona poling method was used, and for studying the surface potential variations - the Kelvin probe method. The photoreaction time constant of the fast response (several seconds) was found to be almost independent of the molecular concentration in the polymer film and of the absorbed light intensity in the bulk of a sample. In contrast, the amplitude of photoinduced changes in the surface potential depends both on the concentration of azobenzene molecules and on the absorbed light intensity in bulk of the host-guest polymer film.

Restricted conformation dynamics of single functionalized perylene bisimide molecules on SiO2 surfaces and in thin polymer films

Intramolecular conformational dynamics caused by the bay groups of perylene bisimide (PBI) molecules have been investigated by single molecule spectroscopy in thin PMMA polymer films and on SiO2 surfaces. All dynamic processes occur in a jump-like fashion on SiO2 but in a likewise continuous way in PMMA. Surface attachment on SiO2 is accomplished by pyridyl functionalization of PBI demonstrating a nearly perpendicular orientation of the long axis of perylene as has been concluded from polarization experiments. This orientation is subject to fluctuations of the molecular orientation and/or conformation, which are considerably reduced in PMMA. According to static and time-dependent fluorescence spectra at least 2 different conformations have been identified.

Synthesis, Ensemble, and Single Molecule Characterization of a Diphenyl-Acetylene Linked Perylenediimide Trimer

Perylenediimide (PDI) dyes have attracted a great deal of attention as they possess excellent photochemical stability, high extinction coefficients, and fluorescence quantum yields. The use of multiple PDI chromophores in one synthetic architecture increases their versatile use and functionality even more. However, bringing multiple chromophores in close proximity also leads to interactions among the chromophores and opens up new photophysical pathways. Here, the synthesis and photophysical characterization, both at the ensemble and single molecule level, of a diphenyl-acetylene linked perylenediimide trimer (3PDIAc) is presented. Förster type energy transfer processes like energy hopping and singlet−singlet annihilation among the chromophores are investigated. Despite the lower singlet−singlet annihilation rate of the phenoxy substituted perylenediimide chromophores (356 ps) versus for example perylenemonoimide (10 ps), the system still behaves as a single photon emitter. Sequential fitting of the dipole emission pattern recorded with defocused wide field imaging of single 3PDIAc, immobilized in a PMMA polymer film, demonstrated that emission can switch between sequential emission of all of the chromophores or emission from one chromophore that likely is the lowest in energy.

The effects of organic additives on photochromism. Part I: the photochromic performance of (E)‐dicyclopropylmethylene‐(2,5‐dimethyl‐3‐furylethylidene)‐succinic anhydride and ferrocene containing dye doped in PMMA polymer film

PurposeTo evaluate the photochromic performance of fulgide 1‐E with ferrocene in polymer matrices.Design/methodology/approachThe fulgide 1‐E with ferrocene dye 2 doped in polymethylmethacrylate was prepared and the effects of UV irradiation were studied using spectrophotometer. The reversible reaction was effected using white light. The effect of heat was also determined.FindingsA film of the brown coloured fulgide 1‐E with ferrocene doped in PMMA polymer was irradiated with ultraviolet light (365 nm), the film turned red. The later colour was partially switched back to the original brown colour when the film was irradiated with a white light. It was found that the rate constants of photocoloration reaction at initial stages are faster than those at late stages. Similarly, the photocoloration reaction was slower than the photobleaching reaction. Photocoloration reaction decreased with the increase of the annealing temperatures, but for photobleaching reaction, the rates were almost similar (at 46 and 82°C). The fatigue resistance of the film was greatly improved when the annealing temperature increased to 82°C.Research limitations/implicationsThe polymethylmethacrylate polymer doped photochromic fulgide 1‐E and ferrocene 2 described in the present paper was prepared and studied. The principle of study established can be applied to any type of polymer or to any type of photochromic compounds.Practical implicationsThe photochromic materials developed can be used for different applications, such as coatings and holography.Originality/valueThe method developed may be used to enhance the performance of photochromic materials.