Improvement of optical properties of pH- sensitive nanolayers coating deposited using Layer-by-Layer technique

Raoufi, Nahid; Surre, F.; Sun, Tao; Grattan, K. T. V.; Rajarajan, Muttukrishnan

doi:10.1109/icsens.2012.6411515

Cited by 3 publications

(4 citation statements)

References 9 publications

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“…This minimum charge density depends on the salt concentration and the salt type; this was investigated [39] by the authors previously and also it was shown that to rely very strongly on the chemical identity of the charged units involved in forming the thin film [40]. Stronger ion pairing will also yield more stable multilayers [2] and moreover, high molecular weight polymers promote the stability of the layers [41][42][43].…”

Section: Resultsmentioning

confidence: 99%

Optical sensor for pH monitoring using a layer-by-layer deposition technique emphasizing enhanced stability and re-usability

Raoufi

Surre

Rajarajan

et al. 2014

Sensors and Actuators B: Chemical

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Section: Resultsmentioning

confidence: 99%

Optical sensor for pH monitoring using a layer-by-layer deposition technique emphasizing enhanced stability and re-usability

Raoufi

Surre

Rajarajan

et al. 2014

Sensors and Actuators B: Chemical

Self Cite

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“…Another of the most common strategies for the design of effective optical fiber pH sensors is based on the use of specific pH indicators such as Prussian Blue (PB) [91], Neutral Red (NR) [76,92,93,94] or Brilliant Yellow (BY) [95,96] as well as fluorescent pH indicator such as HPTS [75,97], among others. In several works, the specific pH indicator can be perfectly dissolved in one of the polyelectrolytes, as it can be observed in [91,92,97].…”

Section: Applications Of the Optical Fiber Sensors Based On Layer-mentioning

confidence: 99%

“…Finally, a highly repetitive behavior (see Figure 13d) is observed by using a same pH step routine (pH 3 and 8, respectively), and the sensor reacted with very short response times (less than 1 s). In other work [94], by using this same multilayer structure of (NR/PAA), two different approaches such as the addition of salt into the polyanion solution and the use of different drying methods are evaluated with the aim to improve the optical properties of the pH-sensitive coating. According to this, the addition of salt which provokes rougher and more porous coatings has produced an enhancement in the sensitivity of the probe from 65 nm/pH unit (no salt) up to 105 nm/pH unit (0.15 M) with a shift in the sensitivity range, whereas drying with nitrogen presents the largest influence on both peak and wavelength because there is a better control over the swelling/deswelling behavior.…”

Section: Applications Of the Optical Fiber Sensors Based On Layer-mentioning

confidence: 99%

Layer-by-Layer Nano-assembly: A Powerful Tool for Optical Fiber Sensing Applications

Rivero

Goicoechea

Arregui

2019

Sensors

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The ability to tune the composition of nanostructured thin films is a hot topic for the design of functional coatings with advanced properties for sensing applications. The control of the structure at the nanoscale level enables an improvement of intrinsic properties (optical, chemical or physical) in comparison with the traditional bulk materials. In this sense, among all the known nanofabrication techniques, the layer-by-layer (LbL) nano-assembly method is a flexible, easily-scalable and versatile approach which makes possible precise control of the coating thickness, composition and structure. The development of sensitive nanocoatings has shown an exceptional growth in optical fiber sensing applications due to their self-assembling ability with oppositely charged components in order to obtain a multilayer structure. This nanoassembly technique is a powerful tool for the incorporation of a wide variety of species (polyelectrolytes, metal/metal oxide nanoparticles, hybrid particles, luminescent materials, dyes or biomolecules) in the resultant multilayer structure for the design of high-performance optical fiber sensors. In this work we present a review of applications related to optical fiber sensors based on advanced LbL coatings in two related research areas of great interest for the scientific community, namely chemical sensing (pH, gases and volatile organic compounds detection) as well as biological/biochemical sensing (proteins, immunoglobulins, antibodies or DNA detection).

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“…Previous reports of ISAM optical pH sensing films include various combinations of polyelectrolytes or polyelectrolytes and dyes, such as poly(diallyldimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA) [13], poly(allylamine hydrochloride) (PAH) and P-Azo [14], Prussian Blue [15], and Neutral Red [16,17]. In addition, these films have been incorporated and analyzed in optical fiber pH sensors.…”

Section: Introductionmentioning

confidence: 99%

Response of Optically Transparent pH Sensing Films to Temperature and Temperature Variations

Topasna

2019

Coatings

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There are numerous applications for thin films based chemical pH sensors, in such areas as biomedical, military, environmental, food, and consumer products. pH sensitive films fabricated through the ionic self-assembled monolayers technique were made of polyelectrolyte polyallylamine hydrochloride and the water-soluble organic dye molecule Direct Yellow 4. The films were monitored in various environmental conditions and for selected periods, at temperatures varying between −13.7 and 46.2 °C. Absorbance measurements and atomic force microscopy performed before and after thermal treatment indicate that for optimized thickness and composition the films maintain their functionality and are not affected by long-term exposure at these temperatures.

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Improvement of optical properties of pH- sensitive nanolayers coating deposited using Layer-by-Layer technique

Cited by 3 publications

References 9 publications

Optical sensor for pH monitoring using a layer-by-layer deposition technique emphasizing enhanced stability and re-usability

Optical sensor for pH monitoring using a layer-by-layer deposition technique emphasizing enhanced stability and re-usability

Layer-by-Layer Nano-assembly: A Powerful Tool for Optical Fiber Sensing Applications

Response of Optically Transparent pH Sensing Films to Temperature and Temperature Variations

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