Nonionic water-soluble poly(acrylamide)s and poly(acrylate)s were synthesized by RAFT and ATRP methods. Similar to the synthesized poly(N-isopropylacrylamide) and poly(N-acryloylpyrrolidine), aqueous solutions of statistical acrylate copolymers bearing two different oligo(ethylene oxide) side chains showed a sharp clouding transition upon heating beyond characteristic temperatures. The temperature of the cloud point can be easily fine tuned by the copolymer composition. As for poly(N-isopropylacrylamide) and poly(N-acryloylpyrrolidine), the cloud-point temperatures of these statistical copolymers are rather insensitive to changes in the molar mass or the NaCl content of the solutions. Also, ternary triblock copolymers containing one permanently hydrophilic block and two different thermoresponsive blocks were synthesized, varying the block sequence systematically. Their aggregation in aqueous solution was followed by turbidimetry and dynamic light scattering. Depending on the heating process and the triblock sequence, micellar aggregates of 40 to 600 nm size were found. The thermally induced aggregation behavior depends sensitively on the block sequence but is also subject to major kinetic effects. For certain block sequences, a thermally induced two-step association is observed when heating beyond the first and second cloud points of the thermoresponsive blocks. However, the thermal-transition temperatures of the block polymers can differ from the thermal-transition temperatures of the individual homopolymers. This may be caused by end-group effects but also by mutual interactions of the different blocks in solution, as physical mixtures of the homopolymers exhibit deviations from a purely additive thermal behavior.

We investigated quantitatively the solubility properties of a number of unsubstituted metal phthalocyanines with various metal atoms such as Co, Cu, Fe, Mg, Mn, Ni, Sn, and Zn. We studied three categories of solvents: conventional solvents, ionic liquids, and acids. The conventional liquids comprised 20 typical representatives from acetone to toluene. We tested two ionic liquids and five acids. For each solution we measured the molar absorption coefficient and the saturation concentration (or estimated these values if the solubility was too low). The absorption coefficients and saturation concentrations were derived from UV−vis absorption measurements of the Q-band. The solution spectra are presented and discussed as well as the chemical properties (stability) of the solutions. ■ INTRODUCTIONMetal phthalocyanines (M-PC), as in Figure 1, have attracted considerable attention because of their unique optical and electronic properties 1 together with their high chemical and thermal stability. 2 They are organic semiconductor molecules 3 with numerous applications such as organic solar cells, 4−8 chemical sensors, 9−12 and electronic devices like field effect transistors 13−15 and optical data storage. 16−18 Recently high efficient organic solar cells containing phthalocyanine molecules were produced. 19 Spectroscopic studies are available on phthalocyanine in vapor, 20 in solids, 21 and in solution. 22 There are also many theoretical studies on their spectroscopic properties. 1,23−29 Unsubstituted metal phthalocyanines are barely soluble in common solvents, 30,31 and little quantitative information is available on their solubility. Therefore many research activities focused on synthesizing soluble phthalocyanines by adding functional groups to the molecule. 32,33 Unfortunately most of the substituted phthalocyanines are not as stable as the unsubstantiated compounds, and their electronic properties are also different from those of the unsubstituted phthalocyanines. 1,34,35 Room temperature wet-technologies like printing and spin coating have numerous advantages in the preparation of organic films with less rigorous preparation conditions. More parameters are available to control the nucleation and growth of the film, like solvent, temperature, and the concentration of the solution. But the general poor solubility of unsubstituted metal phthalocyanines limits their use in low cost wet technologies. 36 In the following article we present a systematic study on the solubility of unsubstituted metal phthalocyanine in a series of various solvents including different types of solvents such as neutral conventional solvents, acids, and ionic liquids. The aim of the study is a systematic quantitative assessment of the solubility of various unsubstituted metal phthalocyanines, their saturation solubilities, and their interactions with the solvents. The solubility was quantified and evaluated by UV−vis spectroscopy.We found only a few molar absorption coefficients of dissolved phthalocyanines published. Kumar et al. 21,22,3...

Six new bifunctional bis(trithiocarbonate)s were explored as RAFT agents for synthesizing amphiphilic triblock copolymers ABA and BAB, with hydrophilic “A” blocks made from N‐isopropylacrylamide and hydrophobic “B” blocks made from styrene. Whereas the extension of poly(N‐isopropylacrylamide) by styrene was not effective, polystyrene macroRAFT agents provided the block copolymers efficiently. End group analysis by 1H NMR spectroscopy supported molar mass analysis and revealed an unexpected side reaction for certain bis(trithiocarbonate)s, namely a fragmentation to simple trithiocarbonates while extruding ethylenetrithiocarbonate. The amphiphilic block copolymers with short polystyrene blocks are directly soluble in water and self‐organize into thermoresponsive micellar aggregates.