Nanofiller aggregation

Interfacial behavior of different silicones was extensively studied, as indicated in Section 3.12.4.6. To add a few more examples, solution behavior of water-soluble polysiloxanes carrying different pendant hydrophilic groups, thus differing in hydrophobicity, was reported.584 A study of the aggregation phenomena of POSS in the presence of amphiphilic PDMS at the air/water interface was conducted in an attempt to elucidate nanofiller-aggregation mechanisms.585 An interesting phenomenon of the spontaneous formation of stable microtopographical surface domains, composed primarily of PDMS surrounded by polyurethane matrix, was observed in the synthesis of a cross-linked PDMS-polyurethane films.586... 

FiUer Experimental radius of nanofiller aggregate R, nm Radius of nanofiller particle r, nm Number of particles in one aggregate N Radins of nanotUler aggregate s fh Eq. (1), nm Radius of nanotiller aggregate l , theEq. (3), nm Radius of nanofiUer aggregate R, the Eq. (8), nm... 

As discussed in the review by Li et al. (2010), if the addition of a small fraction of nanofiller leads to an increase in breakdown strength then, beyond a certain point, this trend is reversed, presumably, as a consequence of increased nanofiller aggregation, which dominates any other factors. Then, the agglomerated nanoparticles behave, effectively, as micron-sized inclusions, the presence of which leads to a reduction in breakdown strength (Roy et al. 2005 Vaughan et al. 2006). This result is consistent with studies in which inclusion of various types were added to polymers (Morshuis et al. 1988), which showed empirically that the presence of sizeable particles degrades breakdown performance. 

Proceeding from the said above, the present work purpose is the theoretical treatment of particulate nanofiller aggregation process and elasticity modulus (reinforcement degree) particulate-filled polymer nanocomposites with due regard for the indicated effect within the framework of irreversible aggregation models and fractal analysis. 

The particulate nanofiller aggregation degree can be evaluated and aggregates diameter quantitative estimation can be performed within the framework of strength dispersive theory [11], where shear yield stress of nanocomposite is determined as follows ... 

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