Micro- and nanostructured sol-gel-based materials for optical chemical sensing (2005–2015)

Barczak, Mariusz; McDonagh, Colette; Wencel, Dorota

doi:10.1007/s00604-016-1863-y

Cited by 39 publications

(18 citation statements)

References 165 publications

(176 reference statements)

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“…Real‐time determination of concentration gradients between the internal environment of the immobilized enzymes and the bulk solution is the best way to assess the significance of the diffusional limitations and to offer a better biocatalyst characterization . There are many available solutions to measure O 2 and pH in homogeneous liquid phase with excellent spatio‐temporal resolution . However, the measurements near‐surface or within solids particles are scarce since they present a high technological complexity and require specialized set‐ups.…”

Section: Spatio‐temporal Resolution Of O2 and Ph Within Immobilized Ementioning

confidence: 99%

“…[17,18] There are many available solutionst om easure O 2 andp Hi nh omogeneous liquid phase with excellent spatio-temporal resolution. [107][108][109][110] However, the measurements near-surface or within solids particles are scarce since they present ahigh technological complexity and requires pecializeds et-ups. The basic principle involves al uminescence indicator embedded within an analyte-permeable polymeric layer.T his is furthers ystem-integrated by controlled deposition as in sensor spots and optical fiber tips, enablingdifferent and often contactless optical readouts.…”

Section: Spatio-temporal Resolutionofo 2 and Ph Within Immobilizedenzmentioning

confidence: 99%

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Single‐Particle Studies to Advance the Characterization of Heterogeneous Biocatalysts

et al. 2018

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Immobilized enzymes have been widely exploited because they work as heterogeneous biocatalysts, allowing their recovery and reutilization and easing the downstream processing once the chemical reactions are completed. Unfortunately, we suffer a lack of analytical methods to characterize those heterogeneous biocatalysts at microscopic and molecular levels with spatio‐temporal resolution, which limits their design and optimization. Single‐particle studies are vital to optimize the performance of immobilized enzymes in micro/nanoscopic environments. In this Concept article, we review different analytical techniques that address single‐particle studies to image the spatial distribution of the enzymes across the solid surfaces, the sub‐particle substrate diffusion, the structural integrity and mobility of the immobilized enzymes inside the solid particles, and the pH and O2 internal gradients. From our view, such sub‐particle information elicited from single‐particle analysis is paramount for the design and fabrication of optimal heterogeneous biocatalyst.

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Section: Spatio‐temporal Resolution Of O2 and Ph Within Immobilized Ementioning

confidence: 99%

Section: Spatio-temporal Resolutionofo 2 and Ph Within Immobilizedenzmentioning

confidence: 99%

Single‐Particle Studies to Advance the Characterization of Heterogeneous Biocatalysts

et al. 2018

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“…Sol-gel reactions of R-and bis-R-alkoxysilanes have been used over the years to synthesize a wide variety of highly porous materials containing hybrid inorganic/organic moieties [1][2][3][4][5][6]. Although historically these types of porous materials have focused on using bridged alkoxysilanes synthesized by acid or base catalysis in a random structural formation, there are many advances in controlling the reactivity that give more focused pore sizes and overall reaction control [7][8][9][10][11][12][13][14]. There have been a few strategies implemented for this, including extensive processing and templation methodologies to maximize porosity and pore-structure stability [10,12,[15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

R-Silsesquioxane-Based Network Polymers by Fluoride Catalyzed Synthesis: An Investigation of Cross-Linker Structure and Its Influence on Porosity

Furgal

2020

Materials

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Silsesquioxane-based networks are an important class of materials that have many applications where high thermal/oxidative stability and porosity are needed simultaneously. However, there is a great desire to be able to design these materials for specialized applications in environmental remediation and medicine. To do so requires a simple synthesis method to make materials with expanded functionalities. In this article, we explore the synthesis of R-silsesquioxane-based porous networks by fluoride catalysis containing methyl, phenyl and vinyl corners (R-Si(OEt) 3 ) combined with four different bis-triethoxysilyl cross-linkers (ethyl, ethylene, acetylene and hexyl). Synthesized materials were then analyzed for their porosity, surface area, thermal stability and general structure. We found that when a specified cage corner (i.e., methyl) is compared across all cross-linkers in two different solvent systems (dichloromethane and acetonitrile), pore size distributions are consistent with cross-linker length, pore sizes tended to be larger and π-bond-containing cross-linkers reduced overall microporosity. Changing to larger cage corners for each of the cross-linkers tended to show decreases in overall surface area, except when both corners and cross-linkers contained π-bonds. These studies will enable further understanding of post-synthesis modifiable silsesquioxane networks.Materials 2020, 13, 1849 2 of 13 of reaction solvent and water content in modifying the overall pore size distributions of a single cross-linker system [29]. Though many reports speculate that the pore sizes obtained in sol-gel reactions are directly related to the bridging groups used, especially for rigid spacers [2,26,[30][31][32], we found that multiple pore size distributions (0.5 to 100 nm) could be obtained by simply changing the reaction solvent for the same bridge. For example, dichloromethane (DCM) favored micropores on the order of 1.2 nm and gel particles, while changing the reaction solvent to acetonitrile (ACN) gave pores centered around 3 nm and favored global gelation of the entire system. All the synthesized materials favored non-polar solvents as expected for organogels based on networked silsesquioxanes.Though high porosity materials with static or non-functionalizable pores are useful in many applications [33][34][35][36], it is often desirable to impart additional functionality to these materials for many specialized uses. such as in biology or environmental remediation. as capture and release agents [2,17,[37][38][39]. These functionalities may include hydrophilic groups, amino-acids and reversible chemistries such as "click" or complexation ligands [40][41][42][43][44]. Many researchers have been working on methods to synthesize active silsesquioxane-based networks, albeit primarily through preformed cage methods. In terms of preformed cage systems, Ervithayasuporn et al. have developed a recyclable methacrylate-POSS (polyhedral oligomeric silsesquioxanes) porous network which can efficiently bind Pd and acts as a catalyst f...

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“…ZnO thin films are processed using methods such as atomic layer deposition (ALD) [7], chemical vapors deposition (CVD) [8], pulsed laser deposition (PLD) [9], RF magnetron sputtering [10], epitaxial growth [11], self-assembly [12], sputtering technique [13], co-precipitation [14], electrodeposition [15], spray pyrolysis [16], and sol-gel method [17]. The sol-gel technique is also used for the fabrication of membranes [18], chemical sensors [19], optical gain media [20,21], electrochemical devices [22], photochromic and non-linear applications [23], and nanomaterials [24]. The sol-gel method is advantageous over other synthetic procedures.…”

Section: Introductionmentioning

confidence: 99%

Sol-Gel-Derived Doped ZnO Thin Films: Processing, Properties, and Applications

Mahmood¹,

Akhtar²

2017

Recent Applications in Sol-Gel Synthesis

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Sol-gel-derived zinc oxide (ZnO)-based materials with an improved microstructure are consumed in electronics and electrical frameworks owing to their crystal structure dependent properties, which can be exploited for optical, electrical, and photocatalytic applications. Despite research articles published each year on the strategies to improve the optoelectronic properties of ZnO, the topic is still actively pursued in literature. This chapter provides an insight into the recent developments for the sol-gel-derived processing of the pure and doped ZnO thin films. It also highlights the challenges and opportunities surrounding the processing of these devices. The recent developments in the synthesis of pure, doped ZnO, and corresponding applications of these films will be discussed in detail. Consequently, the aim of this chapter is to provide an overview of the novel developmental strategies to improve ZnO-based thin films by a sol-gel route with enhanced optical properties for practical applications ranging from optical and electrical circuits to sensing.

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Micro- and nanostructured sol-gel-based materials for optical chemical sensing (2005–2015)

Cited by 39 publications

References 165 publications

Single‐Particle Studies to Advance the Characterization of Heterogeneous Biocatalysts

Single‐Particle Studies to Advance the Characterization of Heterogeneous Biocatalysts

R-Silsesquioxane-Based Network Polymers by Fluoride Catalyzed Synthesis: An Investigation of Cross-Linker Structure and Its Influence on Porosity

Sol-Gel-Derived Doped ZnO Thin Films: Processing, Properties, and Applications

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