Polydispersity index, grafted silica

Number average particle diameters, weight average particle diameters and polydispersity Indexes of polystyrene latex particles synthesized In the presence of MPS-grafted 30N50 silica particles with Increasing MPS grafting densities. 

The polymer under investigation was polydimethylsiloxane (PDMS, 960 kg/mol > Mw >300 kg/mol polydispersity index, M /Mn, <1.3) at room temperature flowing along silica surfaces bearing either adsorbed PDMS chains 11-13) or end grafted PDMS chains (7, 14). Controlled chemistry at the silica - PDMS interface allowed to vary independently the molecular weights and surface densities of the surface anchored PDMS chains. 

However, in a later work Kruk et al. [31] reported the successful use of ATRP for the controlled preparation of brushes inside quite narrow pores (-15 nm diameter) of ordered mesoporous silica with a low polydispersity index (<1.1), as long as the grafted chains do not fill the pore space completely. It is very probable that system-specific issues affect properties of the resulting concave brushes, something that has to be studied further. 

Figure 5.4 Ellipsometric profiles of a PDMS microdroplet. Right The PDMS chain whose viscosity = 420 cP (Mp = 16 kg/mole), polydispersity index. Ip = 1.20 (fractionated sample], and surface tension, y = 21.1 mN/m. Substrate Silicon wafer grafted with hexamethyldisilazane critical surface tension close to 21.5 mN/m. Vertical scale. Angstrom horizontal scale, mm baseline, silica layer lateral resolution, 30 pm. Profiles recorded at 18 h, 44 h, and 95 h after drop deposition. Each step is a flat, compact monolayer of PDMS chains at 2D (right]. (Adapted from N. Fraysse ].

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