Using pH/thermal responsive materials

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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Review of Functional Treatments for Modified Wood

Coatings ◽

10.3390/coatings11030327 ◽

2021 ◽

Vol 11 (3) ◽

pp. 327

Author(s):

Morwenna J. Spear ◽

Simon F. Curling ◽

Athanasios Dimitriou ◽

Graham A. Ormondroyd

Keyword(s):

High Performance ◽

Responsive Materials ◽

Wood Modification ◽

Wide Range ◽

Natural Wood ◽

Impregnation Modification ◽

New Applications ◽

New Generation ◽

Dimensional Instability ◽

Modified Wood

Wood modification is now widely recognized as offering enhanced properties of wood and overcoming issues such as dimensional instability and biodegradability which affect natural wood. Typical wood modification systems use chemical modification, impregnation modification or thermal modification, and these vary in the properties achieved. As control and understanding of the wood modification systems has progressed, further opportunities have arisen to add extra functionalities to the modified wood. These include UV stabilisation, fire retardancy, or enhanced suitability for paints and coatings. Thus, wood may become a multi-functional material through a series of modifications, treatments or reactions, to create a high-performance material with previously impossible properties. In this paper we review systems that combine the well-established wood modification procedures with secondary techniques or modifications to deliver emerging technologies with multi-functionality. The new applications targeted using this additional functionality are diverse and range from increased electrical conductivity, creation of sensors or responsive materials, improvement of wellbeing in the built environment, and enhanced fire and flame protection. We identified two parallel and connected themes: (1) the functionalisation of modified timber and (2) the modification of timber to provide (multi)-functionality. A wide range of nanotechnology concepts have been harnessed by this new generation of wood modifications and wood treatments. As this field is rapidly expanding, we also include within the review trends from current research in order to gauge the state of the art, and likely direction of travel of the industry.

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Acid-Catalysed Liquid-to-Solid Transitioning of Arylazoisoxazole Photoswitches

Chemical Science ◽

10.1039/d1sc03308e ◽

2021 ◽

Author(s):

Luuk Kortekaas ◽

Julian Simke ◽

Niklas Arndt ◽

Marcus Böckmann ◽

Nikos Doltsinis ◽

...

Keyword(s):

Building Blocks ◽

Vital Role ◽

Responsive Materials ◽

Molecular Building Blocks ◽

Physical Changes

Molecular photoswitches play a vital role in the development of responsive materials. These molecular building blocks are particularly attractive when multiple stimuli can be combined to bring about physical changes,...

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Magnetic responsive materials modulate the inflammatory profile of IL-1β conditioned tendon cells

Acta Biomaterialia ◽

10.1016/j.actbio.2020.09.028 ◽

2020 ◽

Vol 117 ◽

pp. 235-245

Author(s):

A. Vinhas ◽

M.T. Rodrigues ◽

A.I. Gonçalves ◽

R.L. Reis ◽

M.E. Gomes

Keyword(s):

Responsive Materials ◽

Tendon Cells ◽

Inflammatory Profile

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Heat‐ and Light‐Responsive Materials Through Pairing Dynamic Thiol–Michael and Coumarin Chemistry

Macromolecular Rapid Communications ◽

10.1002/marc.202100070 ◽

2021 ◽

pp. 2100070

Author(s):

Progyateg Chakma ◽

Shiwanka V. Wanasinghe ◽

Colleen N. Morley ◽

Sebastian C. Francesconi ◽

Kei Saito ◽

...

Keyword(s):

Responsive Materials

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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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Dual Light- and pH-Responsive Composite of Polyazo-Derivative Grafted Cellulose Nanocrystals

Materials ◽

10.3390/ma11091725 ◽

2018 ◽

Vol 11 (9) ◽

pp. 1725 ◽

Cited By ~ 5

Author(s):

Xiaohong Liu ◽

Ming Li ◽

Xuemei Zheng ◽

Elias Retulainen ◽

Shiyu Fu

Keyword(s):

Cellulose Nanocrystals ◽

Photoelectron Spectroscopy ◽

Surface Composition ◽

X Ray Diffraction ◽

Responsive Materials ◽

X Ray ◽

Ph Response ◽

Transmission Electron ◽

Ft Ir ◽

Hexyl Methacrylate

As a type of functional group, azo-derivatives are commonly used to synthesize responsive materials. Cellulose nanocrystals (CNCs), prepared by acid hydrolysis of cotton, were dewatered and reacted with 2-bromoisobuturyl bromide to form a macro-initiator, which grafted 6-[4-(4-methoxyphenyl-azo) phenoxy] hexyl methacrylate (MMAZO) via atom transfer radical polymerization. The successful grafting was supported by Fourier transform infrared spectroscopy (FT-IR) and Solid magnetic resonance carbon spectrum (MAS 13C-NMR). The morphology and surface composition of the poly{6-[4-(4-methoxyphenylazo) phenoxy] hexyl methacrylate} (PMMAZO)-grafted CNCs were confirmed with Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The grafting rate on the macro-initiator of CNCs was over 870%, and the polydispersities of branched polymers were narrow. The crystal structure of CNCs did not change after grafting, as determined by X-ray diffraction (XRD). The polymer PMMAZO improved the thermal stability of cellulose nanocrystals, as shown by thermogravimetry analysis (TGA). Then the PMMAZO-grafted CNCs were mixed with polyurethane and casted to form a composite film. The film showed a significant light and pH response, which may be suitable for visual acid-alkali measurement and reversible optical storage.

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