In contrast to conventional fluorescent polymers featured by large conjugation structures, a new class of fluorescent polymers without any conjugations is gaining great interest in immerging applications beyond the possibility to achieve by the conjugated polymers. Poly(ethylene glycol) (PEG), widely used in biomedical fields for a long time owing to its nontoxicity and nonimmunogenicity, is found to be fluorescence emissive in the solid state and in aqueous solution, though deemed as not fluorescent in numerous reports. Through systematic study under different conditions, the emission is ascribed to the cluster formation of its chains; thereby the blue-shift of the emission with the excitation wavelength was interpreted through the Forster resonance energy transfer. The clusterization was ascertained through size measurements, Fourier transform infrared spectroscopy, NMR analyses, and the dependence on temperature, pH, and nonsolvent presence. Tested in the presence of competitive metal ions, selective emission quenching by Fe 3+ and Cr 6+ was observed. PEG was used as a sensor for the detection of Cr 6+ , Fe 3+ , and H 2 O 2 , outperforming most of the reported sensors alike. Its uses for data encryption and cell imaging were also presented. This work provides therefore a novel face of PEG with great potential in a variety of emerging applications, in particular, as sensors in the biomedical area.

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A theoretical analysis and a morphological prediction of polyacrylate (PA)/ polysiloxane (PSi) latex particles with core/shell morphologies were first conducted based on interfacial tensions and relative volumes of the two polymers in the latex system. The results indicated that the normal core/shell morphology particles (PSi/PA), with hydrophobic polysiloxane as the core and with hydrophilic polyacrylate as the shell, can be easily formed. Although the inverted core/shell morphology particles (PA/PSi) with polyacrylate as the core could not be formed in most cases, even if the fraction volume of polysiloxane was larger than 0.872, which is the smallest value of forming a PA/PSi particle, the PSi/PA particles were unavoidably formed simultaneously with PA/PSi particle formation. The synthesis of PA/PSi particles containing equal amounts of polyacrylate and polysiloxane was then carried out using seeded emulsion polymerization. Before the cyclosiloxane cationic polymerization, 3-methacryloyloxypropyl trimethoxysilane (MATS) was introduced into the polyacrylate seed latex to form an intermediate layer and chemical bonds between the core and the shell polymers. The characterization by transmission electron microscopy (TEM) demonstrated that the perfect PA/PSi core/shell particle is successfully synthesized when both the core and the shell polymers are crosslinked. The experiments showed that both the hardness and water adsorption ratio characteristics of latex films of the PA/PSi particles are in good agreement with those of the polysiloxane film.

Copolymers of methacrylic acid (MAA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) were prepared and their cloud points in aqueous solution were studied as a function of comonomer ratio, solution pH, and presence of hydrophobic comonomers. Under acidic conditions, the cloud point falls below 0 °C for copolymers with between 25% to 60% ether content, because of the formation of hydrophobic H‐bonded ether–acid complexes. The cloud point also decreases with solution pH. For equivalent ether to acid ratios, the cloud point decreases with decreasing PEG chain length, because of the presence of a larger number of hydrophobic methyl and methacrylate groups. Similarly, the cloud point decreases upon incorporation of hydrophobic comonomers such as butyl, lauryl, or glycidyl methacrylates. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6095–6104, 2005

The precipitation polymerization of styrene-trihydroxymethyl propane triacrylate has been carried out using ethanol and an ethanol/water mixture as the solvent. Uniform microspheres with high monomer conversion are achieved within 4 h, a much shorter polymerization time than that reported for the precipitation polymerization of divinyl benzene-styrene in acetonitrile. The results clearly demonstrate that use of water as a co-solvent is indeed very effective to promote the polymerization to high conversion and to obtain uniform microspheres. With no water under the otherwise same experimental conditions, only about 57% of monomer conversion is obtained; while the monomer conversion is remarkably increased to 96% when 12 vol.-% of water is used.