Cage-like octa(3-aminopropyl)silsesquioxane trifluoromethanesulfonate (OAP-POSS-CF₃SO₃) was prepared in higher yield (ca. 93%) with a shorter reaction time (ca. 5–6 h), when the hydrolytic condensation of 3-aminopropyltrimethoxysilane was performed using the superacid trifluoromethanesulfonic acid as a catalyst. The structure of the resulting OAP-POSS-CF₃SO₃ was confirmed mainly by ²⁹Si NMR, MALDI-TOF MS, ESI MS, and IR measurements. It is suggested that the lower pK_a of the acid catalyst is an important factor leading to the improved yield for the preparation of OAP-POSS-CF₃SO₃.

An ion-exchangeable layered polysiloxane containing alkylammonium groups was synthesized by sol–gel reaction of 3-aminopropyltrimethoxysilane (APTMOS) catalyzed by hydrochloric acid; the present reaction system provides a new method for the preparation of layered polysiloxane materials.

A low-crystalline POSS containing two types of alkylammonium groups was successfully prepared by hydrolytic condensation of two types of amino group-containing organotrialkoxysilanes, i.e. AEAPTMOS and APTMOS, using aqueous CF ₃ SO ₃ H, forming an optically transparent film.

An ionic liquid containing a random-structured oligosilsesquioxane (Im-Random-SQ-IL) was successfully prepared by the hydrolytic condensation of 1-methyl-3-[3-(triethoxysilyl)propyl]imidazolium chloride (MTICl) in aqueous bis(trifluoromethanesulfonyl)imide (TFSI). Im-Random-SQ-IL exhibited a glass transition temperature (T_g) at −25 °C as indicated by an endothermic peak in the differential scanning calorimetry (DSC) curve. In addition, fluidity was visually observed at ca. 0 °C, i.e. Im-Random-SQ-IL is a room temperature ionic liquid. Conversely, when the hydrolytic condensation of MTICl was performed using a water/methanol (1 : 19 v/v) solution of TFSI, an ionic liquid containing a cage-like oligosilsesquioxane (Im-Cage-SQ-IL) was obtained. The T_g of Im-Cage-SQ-IL was −22 °C, and its melting temperature (T_m) was 105 °C according to the DSC analysis. In addition, fluidity was observed for this ionic liquid at ca. 100 °C. These results suggest that both the amorphous structure of Im-Random-SQ-IL and the type of substituent groups in the silsesquioxane contributed to the ionic liquid behaviour below room temperature. In addition, these ionic liquids exhibited high thermal stabilities (Im-Random-SQ-IL: T_d3 = 429 °C, T_d5 = 437 °C and T_d10 = 447 °C, Im-Cage-SQ-IL: T_d3 = 427 °C, T_d5 = 436 °C and T_d10 = 446 °C) and relatively high ion conductivities (10⁻⁴–10⁻³ S cm⁻¹, at ∼100 °C).