Thermally switchable polymers achieve controlled Escherichia coli detachment

YesThe thermally triggered release of up to 96% of attached uropathogenic E. coli is achieved on two polymers with opposite changes in surface wettability upon reduction in temperature. This demonstrates that the bacterial attachment to a surface cannot be explained in terms of water contact angle alone; rather, the surface composition of the polymer plays the key role.Wellcome Trust (grant number 085245) and the NIH (grant number R01 DE016516

Deposition of fluorescent NIPAM-based nanoparticles on solid surfaces: quantitative analysis and the factors affecting it

Recently, responsive surfaces have attracted attention due to their potential applications. Reported research have studied the deposition of environmentally responsive particles on different surfaces, qualitatively tested their response to environmental conditions and studied their possible applications. In this work, novel fluorescent temperature-sensitive nanoparticles were synthesized using a surfactant free emulsion polymerization technique: poly(N-isopropylacrylamide-co-5% vinyl cinnamate) (p(NIPAM)5%VC). The new particles were characterized using dynamic light scattering and fluorescence spectroscopy. A novel sensitive method for the quantitative analysis of p(NIPAM) 5% VC using fluorescence spectroscopy was developed to determine the concentration of nanoparticle dispersions. This was further used to quantitatively determine the mass of nanoparticles deposited per unit area of glass pre-treated with acid, glass pre-treated with base, quartz, stainless steel, gold and teflon at 25 °C and 60 °C. Factors affecting the adsorption/desorption of the nanoparticles were studied, including the effect of substrate surface charge, surface roughness (using atomic force microscopy, AFM), hydrophilicity/hydrophobicity and the temperature at which the adsorption/desorption experiments were carried out. The results show that the effect of surface charge is the most significant, followed by that of surface roughness and temperature. Meanwhile, the influence of the hydrophobicity/hydrophilicity of the surface on the adsorption/desorption of nanoparticles appears to be far less significant than the previously mentioned factors

A Fluorescent Thermometer Based on a Pyrene-Labeled Thermoresponsive Polymer

Thermoresponsive polymers that undergo a solubility transition by variation of the temperature are important materials for the development of ‘smart’ materials. In this contribution we exploit the solubility phase transition of poly(methoxy diethylene glycol methacrylate), which is accompanied by a transition from hydrophilic to hydrophobic, for the development of a fluorescent thermometer. To translate the polymer phase transition into a fluorescent response, the polymer was functionalized with pyrene resulting in a change of the emission based on the microenvironment. This approach led to a soluble polymeric fluorescent thermometer with a temperature range from 11 °C to 21 °C. The polymer phase transition that occurs during sensing is studied in detail by dynamic light scattering

Amphiphilic hyperbranched polyelectrolytes: a new type of polysoap

Hyperbranched hydrophobized polyelectrolytes of the ionene type are prepared. They are investigated as a new type of polysoap, with respect to viscosifying behaviour, surface activity and solubilization power. Compared to linear analogues, the visoasifying effect is reduced. Compared to classical polysoap architectures, such as analogous "tail-end-type" and "head-type" polysoaps, the hyperbranched polysoaps behave rather similarly to the "head-type" ones: they exhibit notable surface activity, whereas the solubilization capacity is moderate only