Cross-Linked PVCL Microgels Stabilised with Amphiphilic Grafts

Cross-Linked PVCL Microgels Stabilised with Amphiphilic Grafts 

The size distribution of the PVCL microgel particles synthesised by a batch emulsion polymerisation was monomodal and reasonably narrow [177], regardless of the choice of the emulgator, SDS (El, E2) or macromonomer (E3, E4). The size distributions remain monomodal upon subsequent grafting. A typical size distribution of a PVCL microgel (El) at 20 °C is presented in Fig. 17, as well as the effect of grafting, as a second step, on the hydrodynamic size (El-g). 

The sizes of charged and neutral particles were measured as a function of increasing temperature (Fig. 18) [178]. The thermal collapse of the PVCL particles turned out to be a more or less continuous process, regardless of particle charge and the presence or absence of amphiphilic grafts. The PEO chains bound to the particle surfaces had only a minor effect on the transition temperature. The sizes of the particles in cold water varied from sample 

Sample VCL (g/L- Surfactant (g/L ) Initiator (g/L ) Temperature (°C) Reaction time (h) 

VCL N-vinylcaprolactam, SDS sodium dodecyl sulphate, MACnEO 42 w-methoxy poly-(ethylene oxide)42 undecyl a-methacrylate, KPS potassium persulphate, VA-086 2,2 -azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 

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