Responsive polymers for analytical applications: A review

Distyrylbenzene-based segmented conjugated polymers: Synthesis, thin film morphology and chemosensing of hydrophobic and hydrophilic nitroaromatics in aqueous media

“…Besides, despite the absence of side chains in the polymer architecture which is usually a condition to obtain soluble aromatic polymeric materials, we found that polymer solubilities are notably enhanced when the aromatic segments are tethered by the meta rather than para positions [25,26]; the same finding has been reported for quaterphenylenes linked with oligo(ethylene glycol) spacers [12]. Finally, the frustrated packing of semi-rigid segments causes void spaces that ease analyte exchange, thus making films of these nonaggregating amorphous luminescent materials good candidates for chemosensing by fluorescence quenching [1,3,[25][26][27][28].…”

“…The remarkable development of molecular and polymer electronics relies in a large extent upon the potential of organic material architectures to be tuned for improvement of color, band gap, morphology and other properties required for their optimal performance in specific applications such as chemical and biological sensing [1,2,3], emission [4,5] or storage of light [6]. Conjugated polymers are the paradigm of electronic organic materials and the subject of intense research endeavoring to tailor their luminescence and expand their fields of application [7].…”

“…In this context, an efficacious concept of macromolecular design aiming to customize the physical and electronic properties of conjugated polymers consists in the regular insertion in the polymer backbone of atomic or molecular motifs which tailor the π-conjugation length. Thus, a variety of regularly segmented conjugated polymers (SCPs) have been synthesized by linking aromatic segments of discrete size with spacers such as biphenylene [8], binaphthylene [9], paracyclophane [10], linear alkylene [11,12] and oxyethylene chains [13], oxygen atoms [14], silicon atoms [15,16] and sp 3 -carbon atoms of the norbornylene [17], fluorenylidene [18] and isopropylidene groups [19][20][21] all of which break conjugation in a controlled manner.…”

“…The modification, and even degradation [23], of the photophysical properties of the chromophoric repeating units is an especially acute problem in SCPs with flexible spacers, whose conformational flexibility and amphilicity promote ordering of the anisometric rigid units [12,23]. But when the size of the spacer dwindles down to a single sp 3 carbon atom the gem-chromophores are forced into angular dispositions bringing forth twisted polymer microstructures which introduce a great deal of disorder into polymer morphologies. Therefore, in our studies we focused on the small isopropylidene spacer as the key element in designing regularly SCPs with amorphous morphologies which would ideally present optical properties insensible to the aggregation state.…”

Stimuli-responsive polymers. 11. Highly adaptive poly(urea-amide)s that display solvent, light and heat modulated chiroptical behavior

“…Specific rotations, reported here as deg dm À1 g À1 cm 3 , were evaluated at the sodium D-line (589 nm) with a Perkin Elmer Model 241 polarimeter. Polymer samples were dissolved in specified solvents at concentrations falling between 0.030 and 0.050 g/dL.…”