Types of Polysiloxanes

Polysiloxanes (also known as silicone oils or gums) have a repetitive backbone that consists of two hydrocarbon chains per silicon atom (see Fig. 2.7). These phases are the most widely used for capillary columns because of their wide temperature range (-50 < T < 325 °C, with Rj = R2 = CH3). Approximately 20 types of polysiloxane phases have been commercialised worldwide. 

An MAS Si NMR spectrum typical of these types of polysiloxane is given in Figure 5. 

We were interested in two types of polysiloxane diblock copolymers, both having a hydrophobic PDMS block, the second block consisting either of a hydrophilic PEO block or a hydrophilic polysiloxane block. 

This intramoleciflar cycloreversion may occur from at least 4 SiO bonds [2]. So, several researchers have shown interest in another type of polysiloxane polysilalkylenesiloxanes or hybrid silicones alternating SiO and SiC bonds in their backbones and having the following general formula ... 

LC polymers with paired mesogens in the side branches (cf. Fig. 6.3c) form a peculiar type of nematic copolymers. If the lengths of the aliphatic spacers which join the mesogenic groups to the main chain differ, the nematic mesophase appears, as seen from the comparison of two types of polysiloxanes ... 

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