Stimuli-Responsive Systems in Optical Humidity-Detection Devices

The use of electronic devices to measure Relative Humidity (RH) is widespread. However, under certain circumstances, for example when explosive gases are present, a spark-free method should be used. Here we suggest the use of stimuli-responsive materials, like gelatin and interpenetrated polymers, to detect RH with an optical method. These materials are hydrophilic. When water vapor is absorbed by the films the molecules attach to the films molecular network. The result is that the film thickness increases and their refractive index changes. To detect the change of these two parameters an optical method based on diffraction gratings is employed. Surface diffraction gratings are recorded on the films. Then gratings are placed in an optical configuration that is immersed in a climatic chamber. A light beam is sent to the grating where it is diffracted. Several light orders appear. Due to the absorption of water molecules the films swell and grating surface modulation changes. This implies that the diffracted orders intensity changes. A calibrating plot relating intensity as a function of RH is obtained.

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Water Vapor Sensors Based on the Swelling of Relief Gelatin Gratings

Advances in Materials Science and Engineering ◽

10.1155/2015/584324 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5 ◽

Cited By ~ 2

Author(s):

Sergio Calixto ◽

Miguel V. Andres

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Light Beam ◽

Diffraction Gratings ◽

Fabrication Process ◽

First Order ◽

Novel Device ◽

Intensity Changes ◽

Vapor Sensors ◽

Surface Diffraction

We report on a novel device to measure relative humidity. The sensor is based on surface diffraction gratings made of gelatin. This material swells and shrinks according to the content of water vapor in air. By sending a light beam to the grating, diffracted orders appear. Due to the gelatin swelling or shrinking, first order intensity changes according to the relative humidity. Calibration curves relating intensity versus relative humidity have been found. The fabrication process of diffraction gratings and the testing of the prototype sensing devices are described.

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Smart Polymers and their Applications: A Review

International Journal of Current Pharmaceutical Review and Research ◽

10.25258/ijcprr.v8i03.9220 ◽

2017 ◽

Vol 8 (03) ◽

Author(s):

Gore S. A. ◽

Gholve S. B. ◽

Savalsure S. M. ◽

Ghodake K. B. ◽

Bhusnure O. G. ◽

...

Keyword(s):

Oil Recovery ◽

Water Soluble ◽

Solution Temperature ◽

Smart Polymers ◽

Stimuli Responsive ◽

Responsive Materials ◽

Water Soluble Polymers ◽

Commercial Applications ◽

Stimuli Sensitive ◽

External Stimuli

Smart polymers are materials that respond to small external stimuli. These are also referred as stimuli responsive materials or intelligent materials. Smart polymers that can exhibit stimuli-sensitive properties are becoming important in many commercial applications. These polymers can change shape, strength and pore size based on external factors such as temperature, pH and stress. The stimuli include salt, UV irradiation, temperature, pH, magnetic or electric field, ionic factors etc. Smart polymers are very promising applicants in drug delivery, tissue engineering, cell culture, gene carriers, textile engineering, oil recovery, radioactive wastage and protein purification. The study is focused on the entire features of smart polymers and their most recent and relevant applications. Water soluble polymers with tunable lower critical solution temperature (LCST) are of increasing interest for biological applications such as cell patterning, smart drug release, DNA sequencing etc.

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Sensitive Mechanocontrolled Luminescence in Cross-Linked Polymer Films

10.26434/chemrxiv.9943943.v1 ◽

2019 ◽

Author(s):

Ayumu Karimata ◽

Pradnya Patil ◽

Eugene Khaskin ◽

Sébastien Lapointe ◽

robert fayzullin ◽

...

Keyword(s):

Mechanical Stress ◽

Polymer Films ◽

Soft Matter ◽

Small Strain ◽

Visual Methods ◽

Photoluminescence Intensity ◽

Stimuli Responsive ◽

Responsive Materials ◽

Highly Sensitive ◽

Mechanical Stretching

Direct translation of mechanical force into changes in chemical behavior on a molecular level has important implication not only for the fundamental understanding of mechanochemical processes, but also for the development of new stimuli-responsive materials. In particular, detection of mechanical stress in polymers via non-destructive methods is important in order to prevent material failure and to study the mechanical properties of soft matter. Herein, we report that highly sensitive changes in photoluminescence intensity can be observed in response to the mechanical stretching of cross-linked polymer films when using stable, (pyridinophane)Cu-based dynamic mechanophores. Upon stretching, the luminescence intensity increases in a fast and reversible manner even at small strain (< 50%) and applied stress (< 0.1 MPa) values. Such sensitivity is unprecedented when compared to previously reported systems based on organic mechanophores. The system also allows for the detection of weak mechanical stress by spectroscopic measurements or by direct visual methods.<br>

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Redox-State Dependent Spectroscopic Properties of Porous Organic Polymers Containing Furan, Thiophene, and Selenophene

Australian Journal of Chemistry ◽

10.1071/ch17335 ◽

2017 ◽

Vol 70 (11) ◽

pp. 1227 ◽

Cited By ~ 2

Author(s):

Carol Hua ◽

Stone Woo ◽

Aditya Rawal ◽

Floriana Tuna ◽

James M. Hook ◽

...

Keyword(s):

Solid State ◽

Redox State ◽

Spectroscopic Properties ◽

Structural Features ◽

Organic Polymers ◽

Stimuli Responsive ◽

Porous Organic Polymers ◽

Paramagnetic Resonance ◽

Responsive Materials ◽

State Dependent

A series of electroactive triarylamine porous organic polymers (POPs) with furan, thiophene, and selenophene (POP-O, POP-S, and POP-Se) linkers have been synthesised and their electronic and spectroscopic properties investigated as a function of redox state. Solid state NMR provided insight into the structural features of the POPs, while in situ solid state Vis-NIR and electron paramagnetic resonance spectroelectrochemistry showed that the distinct redox states in POP-S could be reversibly accessed. The development of redox-active porous organic polymers with heterocyclic linkers affords their potential application as stimuli responsive materials in gas storage, catalysis, and as electrochromic materials.

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Shape memory polymer network with thermally distinct elasticity and plasticity

Science Advances ◽

10.1126/sciadv.1501297 ◽

2016 ◽

Vol 2 (1) ◽

pp. e1501297 ◽

Cited By ~ 232

Author(s):

Qian Zhao ◽

Weike Zou ◽

Yingwu Luo ◽

Tao Xie

Keyword(s):

Shape Memory ◽

Molecular Design ◽

Shape Change ◽

Shape Memory Polymer ◽

Polymer Network ◽

Stimuli Responsive ◽

Responsive Materials ◽

Device Applications ◽

Temperature Ranges ◽

Rational Molecular Design

Stimuli-responsive materials with sophisticated yet controllable shape-changing behaviors are highly desirable for real-world device applications. Among various shape-changing materials, the elastic nature of shape memory polymers allows fixation of temporary shapes that can recover on demand, whereas polymers with exchangeable bonds can undergo permanent shape change via plasticity. We integrate the elasticity and plasticity into a single polymer network. Rational molecular design allows these two opposite behaviors to be realized at different temperature ranges without any overlap. By exploring the cumulative nature of the plasticity, we demonstrate easy manipulation of highly complex shapes that is otherwise extremely challenging. The dynamic shape-changing behavior paves a new way for fabricating geometrically complex multifunctional devices.

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