A facile PDMS coating approach to room-temperature gas sensors with high humidity resistance and long-term stability

Gao, Zhimin; Song, Guoshuai; Zhang, Xuemin; Li, Qian; Yang, Shuang; Wang, Tieqiang; Li, Yunong; Zhang, Liying; Guo, Lei; Fu, Yu

doi:10.1016/j.snb.2020.128810

“…The observed WCA is therefore prone to error as a material with high intrinsic hydrophobicity can display a lower WCA than a material of lower intrinsic hydrophobicity if it has more suitable roughness. 62,63 This behavior is demonstrated by AC as the intrinsically hydrophobic pores resulted in a slower, gradual water uptake until it is capped by the material surface area. The increasing order of 80% P/P 0 water uptake quantity can therefore be summarized as follows: MIL-PDMS-Dow-6 < AC < MIL-PDMS-Sigma-6 < MIL- Toluene adsorption isotherms.…”

Section: Resultsmentioning

confidence: 98%

Polydimethyl siloxane/MIL-101 Composites for Enhanced Toluene Adsorption in the Presence of Humidity

Azmi¹,

Cherukupally²,

Hunter‐Sellars³

et al. 2021

Preprint

0

View full text Add to dashboard Cite

<div><b>ABSTRACT</b> <br></div><div><br></div><div> Competition between atmospheric moisture and volatile organic compounds (VOCs) for an adsorbent’s sites can significantly impact its VOC removal efficiency. The development of moisture-tolerant adsorbents is essential to address this issue. A vapor phase deposition process using polydimethylsiloxane (PDMS) has created a hydrophobic form of the highly porous, normally hydrophilic, MOF MIL-101. After optimizing the PDMS vapor deposition time and molecular weights, hydrophobicity index calculations verified the improved hydrophobicity of the coated MOF (MIL-PDMS-Sigma-0.25) over its pristine form. The surface area, pore volume as well as single component vapor adsorption of water and toluene capacities were also preserved, resulting to similar performance to MIL-101. Toluene-water vapor co-adsorption experiments were conducted at 40% RH using two toluene concentrations: 0.5% P/P<sub>0</sub> and 10% P/P<sub>0</sub>, mimicking environmental VOC and industrial concentrations, respectively. At 0.5% P/P<sub>0</sub>, MIL-PDMS-Sigma-0.25 exhibited 60% higher adsorption capacity and twice the rate of toluene capture relative to pristine MIL-101, as well as a 3-fold higher toluene uptake relative to a commercial activated carbon. Preliminary adsorbent regeneration experiments confirm the stability and performance of MIL-PDMS-Sigma-0.25. Using a simple vapor phase modification, this new MOF-composite material offers superior competitive toluene vapor uptake in humidified real-world conditions at VOC concentrations. </div>

show abstract

“…Three kinds of polymers with different molecular structures and polarities—PAA [ 43 ], PMMA [ 44 ] and PDMS [ 45 ]—are widely employed as functional polymer films of gas sensors. Here, these polymers were utilized in our designed SERS gas sensors.…”

Section: Resultsmentioning

confidence: 99%

SERS Gas Sensors Based on Multiple Polymer Films with High Design Flexibility for Gas Recognition

Chen

¹

,

Guo

²

,

Sassa

³

et al. 2021

Sensors

View full text Add to dashboard Cite

The Surface-Enhanced Raman Scattering (SERS) technique is utilized to fabricate sensors for gas detection due to its rapid detection speed and high sensitivity. However, gases with similar molecular structures are difficult to directly discriminate using SERS gas sensors because there are characteristic peak overlaps in the Raman spectra. Here, we proposed a multiple SERS gas sensor matrix via a spin-coating functional polymer to enhance the gas recognition capability. Poly (acrylic acid) (PAA), Poly (methyl methacrylate) (PMMA) and Polydimethylsiloxane (PDMS) were employed to fabricate the polymer film. The high design flexibility of the two-layer film was realized by the layer-by-layer method with 2 one-layer films. The SERS gas sensor coated by different polymer films showed a distinct affinity to target gases. The principle component analysis (PCA) algorithm was used for the further clustering of gas molecules. Three target gases, phenethyl alcohol, acetophenone and anethole, were perfectly discriminated, as the characteristic variables in the response matrix constructed by the combination of gas responses obtained 3 one-layer and 3 two-layer film-coated sensors. This research provides a new SERS sensing approach for recognizing gases with similar molecular structures.

show abstract

“…MIL-PDMS-Dow-0.25 exhibited some pore volume reduction which may be associated with greater pore space occupation by this bulkier and higher molecular weight PDMS. 49,63 However, the thickness of the PDMS layers needs precise control to achieve the required degree of wettability change without causing pore blockage.…”

Section: Resultsmentioning

confidence: 99%

Polydimethyl siloxane/MIL-101 Composites for Enhanced Toluene Adsorption in the Presence of Humidity

Azmi¹,

Cherukupally²,

Hunter‐Sellars³

et al. 2021

Preprint

0

View full text Add to dashboard Cite

<div><b>ABSTRACT</b> <br></div><div><br></div><div> Competition between atmospheric moisture and volatile organic compounds (VOCs) for an adsorbent’s sites can significantly impact its VOC removal efficiency. The development of moisture-tolerant adsorbents is essential to address this issue. A vapor phase deposition process using polydimethylsiloxane (PDMS) has created a hydrophobic form of the highly porous, normally hydrophilic, MOF MIL-101. After optimizing the PDMS vapor deposition time and molecular weights, hydrophobicity index calculations verified the improved hydrophobicity of the coated MOF (MIL-PDMS-Sigma-0.25) over its pristine form. The surface area, pore volume as well as single component vapor adsorption of water and toluene capacities were also preserved, resulting to similar performance to MIL-101. Toluene-water vapor co-adsorption experiments were conducted at 40% RH using two toluene concentrations: 0.5% P/P<sub>0</sub> and 10% P/P<sub>0</sub>, mimicking environmental VOC and industrial concentrations, respectively. At 0.5% P/P<sub>0</sub>, MIL-PDMS-Sigma-0.25 exhibited 60% higher adsorption capacity and twice the rate of toluene capture relative to pristine MIL-101, as well as a 3-fold higher toluene uptake relative to a commercial activated carbon. Preliminary adsorbent regeneration experiments confirm the stability and performance of MIL-PDMS-Sigma-0.25. Using a simple vapor phase modification, this new MOF-composite material offers superior competitive toluene vapor uptake in humidified real-world conditions at VOC concentrations. </div>

show abstract

A facile PDMS coating approach to room-temperature gas sensors with high humidity resistance and long-term stability

Cited by 86 publications

References 44 publications

Polydimethyl siloxane/MIL-101 Composites for Enhanced Toluene Adsorption in the Presence of Humidity

Polydimethyl siloxane/MIL-101 Composites for Enhanced Toluene Adsorption in the Presence of Humidity

SERS Gas Sensors Based on Multiple Polymer Films with High Design Flexibility for Gas Recognition

Polydimethyl siloxane/MIL-101 Composites for Enhanced Toluene Adsorption in the Presence of Humidity

Contact Info

Product

Resources

About