Facile Functionalization of Poly(Dimethylsiloxane) Elastomer by Varying Content of Hydridosilyl Groups in a Crosslinker

Abstract

Crosslinked poly(dimethylsiloxane) (PDMS) has been widely used as a dielectric elastomer for electrically driven actuators because it exhibits high elasticity, low initial modulus, and excellent moldability in spite of low dielectric constant. However, further improvement in the characteristics of the PDMS elastomer is not easy due to its chemical non-reactivity. Here, we report a simple method for functionalizing the elastomer by varying content of hydridosilyl groups in PDMS acted as a crosslinker. We synthesized poly(dimethylsiloxane-co-methylvinylsiloxane) (VPDMS) and poly(dimethylsiloxane-co-methylsiloxane) (HPDMS). Tri(ethylene glycol) divinyl ether (TEGDE) as a polar molecule was added to the mixture of VPDMS and HPDMS. TEGDE was reacted to the hydridosilyl group in HPDMS during crosslinking between VPDMS and HPDMS in the presence of platinum as a catalyst. Permittivity of the crosslinked film increased from ca. 25 to 36 pF/m at 10 kHz without a decline in other physical properties such as transparency and elasticity (T > 85%, E ~150 kPa, ɛ ~270%). It depends on the hydridosilyl group content of HPDMS. The chemical introduction of a new molecule into the hydridosilyl group in HPDMS during crosslinking would provide a facile, effective method of modifying the PDMS elastomers.

Monolithic focus-tunable lens technology enabled by disk-type dielectric-elastomer actuators

“…In the optimal elastomer synthesis, we use a poly(dimethylsiloxane- co -methylvinyl-siloxane) and poly(dimethylsiloxane- co -methylsiloxane) compound at a mixing ratio 95:5 wt%. Initial modulus, maximum strain, and dielectric constant of this optimal elastomer film are 390 kPa, 310%, and 2.8 at 1 kHz, respectively, as described in our recent report 19 . Therein, we provide comprehensive information on polymer synthesis procedures and characterizations for chemical, mechanical, and optical properties in greater detail.…”

“…Various lens structures based on electro-active polymer actuators have been proposed toward this end 8 – 16 , 18 , 19 . Liquid-filled elastomer membrane structures take advantages of high physical mobility of the lens-forming optical fluid to yield wide tuning ranges over 100% of an unforced focal length and a response time ~ 0.2 ms 8 – 12 .…”

Dielectric Elastomers UV-Cured from Poly(dimethylsiloxane) Solution in Vinyl Acetate

“…Next, 1.9 mL of 37% hydrochloric acid and 7.5 mL of distilled water were added to the monomers as a catalyst. The detailed polymerization condition, purification method, etc., are shown in our previous report [13]. Yield: 32.9 g (90%).…”

“…Supplementary Materials: The following are available online at http://www.mdpi.com/2073-4360/12/11/2660/s1, Figure S1: IR (a), 1 H-NMR (b), 13 C-NMR (c), and GPC (d) spectra of VPDMS, Figure S2: Stress-strain curves (a) and dielectric permittivity (b) of the PDMS films prepared from Sylgard 184 TM and Elastosil P7670 TM , Figure S3: Water contact angles of the UV-cured film prepared from the V10 solution before (a) and after (b) saponification, Table S1: UV lamp intensity applied on the solution layers.…”

“…Nevertheless, PDMSs have been used as a shapable material for nanoimprint stamps, microfluidic chips, electronic skins, wearable sensors, and actuators owing to their transparency, biocompatibility, and flexibility, in addition to their moldability [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. However, the other characteristics such as hydrophilicity and dielectric permittivity need to be tuned or improved for effective application of PDMS to the appropriate devices [ 11 , 12 , 13 ]. PDMS can be modified via polymer reactions or blending methods.…”