New Processable, Functionalizable Polydiacetylenes

Yarimaga

et al. 2011

Adv Funct Materials

The synthesis, characterization, and functionalization of polydiacetylene (PDA) networks on solid substrates is presented. A highly transparent and cross-linked diacetylene fi lm of DCDDA-bis-BA on a solid substrate is prepared fi rst by tailoring the monomers with organoboronic acid moieties as pendant side groups and consequent drop-casting and dehydration steps. Precisely controlled thermal curing plays a key role to obtain properly aligned diacetylene monomers that are closely packed between the boronic acid derived anhydride structures. A second cross-linking, which occurs by polymerization of the diacetylene monomers with UV irradiation, induces a transparent to blue color shift. Accordingly, colored image patterns are readily available by polymerization through a photomask. The color change that takes place as a response to various organic solvents can be simply detected by naked eyes. The thermofl uorescence change of PDA networks is demonstrated to be an effective method by which to obtain the microscale temperature distribution of thermal systems. The ease of fi lm formation and stress-induced blue-to-red color change with a simultaneous fl uorescence generation features of the network structure should fi nd a great utility in a wide range of chemical and thermal sensing platforms.

Section: Introductionmentioning

confidence: 99%

Network Polydiacetylene Films: Preparation, Patterning, and Sensor Applications

Yarimaga

et al. 2011

Adv Funct Materials

Handbook of Stimuli‐Responsive Materials

“…Both side-and main-chain azobenzene-substituted polymers with good stability, rigidity, and ease of processability involve synthetic routes either using direct polymerization of azobenzene-functionalized monomers or postfunctionalization, where the chromophores are introduced to reactive precursor polymers without harsh polymerization conditions. For side-and main-chain azobenzene polymers, imides [47], esters [48], isocyanates [49], acrylates [50], methacrylates [51], urethanes [52], ethers [53], organometallic ferrocene polymers [54], dendrimers [55], and conjugated polydiacetylenes [56] have been utilized. Selected examples of azobenzene-containing polymer repeating units of (i) side chain, (ii) epoxy, (iii) organometallic ferrocene, (iv) main chain, and (v) conjugated polydiacetlylene are illustrated in Figure 9.4.…”

Section: Azobenzenesmentioning

confidence: 99%

Photochromic Responses in Polymer Matrices

Ramachandran

Urban

2011

IntroductionMany concepts of photochromic systems have been inspired by nature. An illustrative example is the reversible shape changes of the photoreceptor molecule rhodopsin in eyes that produces a cascade of molecular rearrangements responding to light illumination [1]. Upon photoexcitation, all-trans retinal undergoes isomerization to 11-cis across the double bond, thus causing shape changes. Although this event occurs at the angstrom (Å) level, there are many molecular interconnected events and responses that are not fully understood. Similar processes have been observed in certain molecules in materials chemistry, although on a much smaller and at a less-orchestrated scale. These are known as photochromic molecules, which were discovered over 150 years ago in an organic crystal of tetracene, and later on, in inorganic and organometallic materials [2][3][4]. In spite of a long research history, a quest for new photochromic materials continues. Color changes induced by ultraviolet (UV) radiation caused by trans − − cis isomerization, ring opening-closing reactions, inter-or intramolecular charge transfer, or bimolecular cycloaddition reactions are of particular interest. To make use of their photochromic behavior in various applications, photochromic entities are often incorporated into polymer matrices.While creating individual molecules and understanding their electronic properties facilitated further advances in understanding molecular mechanisms governing photochromism, useful applications require fabrication into films, sheets, fibers, or beads. This is typically achieved by incorporating photochromic molecules into macromolecular matrices by doping or dispersing, or covalently attaching them onto a polymer backbone. Since photoisomerization of chromophores alter equilibrium conformations, the dimensions of the surrounding polymer matrix play an essential role in spatial rearrangements. The dimensional classifications of the matrix effect have been extensively examined [5], with notable applications in ophthalmic lens, optical storage media, photosensors, and biomedical devices. Furthermore, the kinetics of conformational changes of polymers with photochromic moieties depends upon their physical or chemical incorporation into the matrix [6]. As one Handbook of Stimuli-Responsive Materials. Edited by Marek W. Urban

High Performance Polymers

“…[38][39][40][41] Many of the cured products were characterized by good mechanical and thermal properties and chemical resistance. Additionally, the unsaturated diacetylene groups in polymer backbone also conceive many other novel properties such as optical [42][43][44] and thermochromic properties. 45,46 Although numerous monomers containing propargyl ether-ended unit or pyridyl ring had been designed and synthesized, the monomers simultaneously containing these function groups had been reported less.…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of diacetylene–containing polymer prepared from propargyl-terminated monomer with pyridine

Yang

Jiang

et al. 2016

A novel diacetylene-containing main chain-type polymer, poly[2,6-bis(4-propargyl-oxy-benzoyl)pyridine] (P 1 ), was synthesized via oxidative coupling reaction with a new propargyl-terminated monomer, 2,6-bis(4-propargyl-oxy-benzoyl)pyridine (M 1 ), which was incorporated a substituted pyridine into the molecular chain of model monomer, 4,4 0 -bis(propargyl-oxy)benzophenone (M 0 ). The structures of the new monomer and the resulting polymer were verified by Fourier transform infrared and proton nuclear magnetic resonance spectroscopies. Differential scanning calorimetry was used to investigate the curing behaviors of M 1 and P 1 . The onset curing temperature of M 1 was 199.0 C, and the exothermic enthalpy of M 1 was 973.4 J g À1 , while the initial curing temperature for polymer P 1 reduced by 48 C and the exothermic enthalpy was almost half. Thermogravimetric analysis (TGA) showed the excellent thermal stabilities of M 1 and its polymer in argon atmosphere (the decomposition temperatures at 5% weight loss were 446 C for M 1 and 370 C for P 1 and their char yields at 800 C exceeded 71%). The above TGA data were superior to that of the model monomer (M 0 ) and its polymer (P 0 ) under the same conditions.