scholarly journals Study on the Effect of 1-Butanol Soluble Lignin on Temperature-Sensitive Gel

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1109 ◽  
Author(s):  
Pan Jiang ◽  
Yi Cheng ◽  
Sheng Yu ◽  
Jie Lu ◽  
Haisong Wang
Keyword(s):  
Environmental Temperature ◽  
Hydroxyl Group ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Stimuli Responsive ◽  
Agricultural Field ◽  
Absorption Properties ◽  
Critical Solution Temperature ◽  
Temperature Sensitive Hydrogel ◽  
Soluble Lignin

A protocol for the fractionation of lignin with 1-butanol as solvent has been proposed in order to improve the utilization of industry alkali lignin. 1-butanol soluble lignin (BSL) was used as a building block for temperature-sensitive hydrogel with N-isopropylacrylamide (NIPAAm) through graft polymerization. The result shows that 1-butanol fractionation is an effective method to improve the molecular weight homogeneity of lignin (PDI, 2.5 to 1.83) and increase the hydroxyl group content (0.585–1.793 mmol/g). The incorporation of BSL into the temperature-sensitive hydrogel can enhance the thermal stability and increase the hydrophobicity of the gel, which leads to a decrease in lower critical solution temperature (LCST). In addition, the compression strength, swelling ratio, and pore size of the gel can be adjusted by the dosage of lignin. This stimuli-responsive gel, with an LCST around 32 °C, is expected to be applied in the agricultural field as a pesticide carrier by stimulating release and absorption properties based on the change in natural environmental temperature.

scholarly journals Thermo- and Photoresponsive Behaviors of Dual-Stimuli-Responsive Organogels Consisting of Homopolymers of Coumarin-Containing Methacrylate

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 329
Author(s):  
Seidai Okada ◽  
Eriko Sato
Keyword(s):  
Functional Group ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Critical Solution Temperature ◽  
Equilibrium Degree ◽  
Stimuli Responsive Polymers ◽  
Responsive Polymers ◽  
Dual Functional ◽  
Wide Range ◽  
Increasing Temperature

Coumarin-containing vinyl homopolymers, such as poly(7-methacryloyloxycoumarin) (P1a) and poly(7-(2′-methacryloyloxyethoxy)coumarin) (P1b), show a lower critical solution temperature (LCST) in chloroform, which can be controlled by the [2 + 2] photochemical cycloaddition of the coumarin moiety, and they are recognized as monofunctional dual-stimuli-responsive polymers. A single functional group of monofunctional dual-stimuli-responsive polymers responds to dual stimuli and can be introduced more uniformly and densely than those of dual-functional dual-stimuli-responsive polymers. In this study, considering a wide range of applications, organogels consisting of P1a and P1b, i.e., P1a-gel and P1b-gel, respectively, were synthesized, and their thermo- and photoresponsive behaviors in chloroform were investigated in detail. P1a-gel and P1b-gel in a swollen state (transparent) exhibited phase separation (turbid) through a temperature jump and reached a shrunken state (transparent), i.e., an equilibrium state, over time. Moreover, the equilibrium degree of swelling decreased non-linearly with increasing temperature. Furthermore, different thermoresponsive sites were photopatterned on the organogel through the photodimerization of the coumarin unit. The organogels consisting of homopolymers of coumarin-containing methacrylate exhibited unique thermo- and photoresponsivities and behaved as monofunctional dual-stimuli-responsive organogels.

Bio-inspired Passive Skin Cooling for Handheld Microelectronics Devices

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Zhi Huang ◽  
Xinsheng Zhang ◽  
Ming Zhou ◽  
Xiaoding Xu ◽  
Xianzheng Zhang ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Handheld Devices ◽  
Solution Temperature ◽  
Passive Cooling ◽  
Temperature Sensitive ◽  
Operation System ◽  
Critical Solution Temperature ◽  
Handheld Device ◽  
Skin Cooling ◽  
Cooling Technology

Increasing functionality demands more heat dissipation from the skin of handheld devices. The maximum amount of heat that can be dissipated passively, prescribed by the natural convection and blackbody radiation theories, is becoming the bottleneck. In this letter, we propose a novel bio-inspirited technique that may overcome this passive cooling limit. It is made possible by using a biomimetic skin capable of perspiration on demand. The key component of the biomimetic skin is a thin layer of temperature sensitive hydro gel (TSHG). The TSHG layer can sweat the skin with moisture when the skin temperature is higher than the TSHG’s lower critical solution temperature (LCST), and thus boost the heat dissipation rate through evaporation. The TSHG layer can absorb moisture at low temperature to replenish. With this novel passive cooling technology, a handheld device can have nearly four times more power beyond the traditional passive cooling limit, and may be powerful enough to run a desktop operation system like a full functional personal computer.

scholarly journals Thickness-Dependent Swelling Behavior of Vapor-Deposited Hydrogel Thin Films

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 757 ◽  
Author(s):  
Fabian Muralter ◽  
Alberto Perrotta ◽  
Anna Maria Coclite
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Chemical Vapor ◽  
Solution Temperature ◽  
Cross Linking ◽  
Temperature Sensitive ◽  
Critical Solution Temperature ◽  
Precise Control ◽  
Initiated Chemical Vapor Deposition ◽  
Deposited Film

Hydrogel thin films containing temperature sensitive chemical functionalities (such as N-isopropylacrylamide, NIPAAm) are particularly interesting for sensor and actuator setups. Complex 3D structures can be conformally coated by the solvent free technique initiated Chemical Vapor Deposition, with precise control over chemical composition and film thickness. In this study, NIPAAm-based thin films with film thicknesses ranging from tens to several hundreds of nanometers and with different amounts of cross-linking were deposited. Above the lower critical solution temperature (LCST), these films repel out water and hence shrink. The amount of cross-linking and the deposited film thickness were successfully identified to both affect shape and position of the LCST transition of these systems: a promising basis for tuning response properties.

THERMOSENSITIVE NANOPARTICLES CONJUGATING WITH CD34 ANTIBODY AND ITS SOLUTION PEROPERTIES

2006 ◽  
Vol 18 (05) ◽  
pp. 222-228 ◽  
Author(s):  
CHUN-TE TAO ◽  
TAI-HORNG YOUNG
Keyword(s):  
Controlled Release ◽  
Cloud Point ◽  
Lower Critical Solution Temperature ◽  
Homogeneous Solution ◽  
The Body ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Critical Solution Temperature ◽  
Human Cd34 ◽  
Collapse Temperature

Poly N-isopropylacrylamide (PNIPAAm) is a well-known temperature-sensitive polymer. When the temperature is higher than the lower critical solution temperature (LCST), PNIPAAm aquous solution is cloudy (phase separation occurred). In contrast, when the temperature is lower than the LCST, PNIPAAm is soluble in water (a homogeneous solution). The lower critical solution temperature (LCST) in aqueous solution of PNIPAAm was about 32~33°C. We prepared nano-scaled PNIPAAm particles containing carboxylic group on their surfaces by introducing acrylic acid monomer. The carboxylic groups were applied to conjugate with the amino group of the CD34 antibody. This immuno-conjugate can be applied on targeting the human CD34 positive cells, peripheral blood progenitor cells included, for cell purification and drug controlled release. In order to the active responding of controlled release of the conjugate in the body influenced by temperature, we hope to estimate the shifting of the gel-collapse temperature or cloud point of the immuno-conjugates by dynamic light scattering (DLS) and UV absorption. The results show that the gel-collapse temperature of the nano-particle was not significantly affected by the content of AA between 1.5~5 mol%. However, cloud point of the solution was elevated by the conjugation of CD34 antibody to 37°C. When CD34-conjugated particle was subsequently incorporated with recombinant FLT3-ligand, which is a smaller molecule compare to CD34 antibody, cloud point of the solution was not affected.

Key Factors to Prepare Polyelectrolytes Showing Temperature-Sensitive Lower Critical Solution Temperature-type Phase Transitions in Water

2012 ◽  
Vol 65 (1) ◽  
pp. 91 ◽  
Author(s):  
Yuki Kohno ◽  
Hiroyuki Ohno
Keyword(s):  
Phase Transition ◽  
Lower Critical Solution Temperature ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Phase Behaviour ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Key Factors ◽  
Critical Solution Temperature ◽  
Type Phase

Tetrabutylphosphonium styrenesulfonate and its homopolymer showed a lower critical solution temperature-type phase transition in water. As the hydrophobicity of these monomeric and polymeric salts affects phase behaviour, the phase transition temperature of the polyelectrolyte was changed by the introduction of monomers having different alkyl chain length on the phosphonium cations.

scholarly journals Novel Thermosensitive Core–Shell Surface Molecularly Imprinted Polymers Based on SiO2 for the Selective Adsorption of Sulfamethazine

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2067 ◽  
Author(s):  
Weihong Huang ◽  
Yujie Qing ◽  
Ningwei Wang ◽  
Yi Lu ◽  
Tianshu Liu ◽  
...  
Keyword(s):  
Selective Adsorption ◽  
Solution Temperature ◽  
Core Shell ◽  
Temperature Sensitive ◽  
Critical Solution Temperature ◽  
Molecularly Imprinted ◽  
Surface Polymerization ◽  
Adsorption Temperature ◽  
Polymerization Method ◽  
Experimental Group

In this research, a novel, sulfamethazine, thermosensitive, molecularly-imprinted polymer (MIP) with an obvious core–shell structure for the enrichment of sulfamethazine (SMZ), which involved temperature sensitive monomer N-Isopropylacrylamide, functional monomer methacrylic acid and cross-linking agents ethyleneglycol dimethacrylate (EGDMA) and N,N′-methylenebisacrylamide, was successfully compounded using the surface polymerization method. To ensure the best experimental group, we designed and compared three groups of controlled experiments of MIPs with different crosslinking agents. When the adsorption temperature was almost the lower critical solution temperature (LCST) of Poly(N-Isopropylacrylamide), the preparative MIPs showed outstanding adsorption capacity and specific identification to sulfamethazine. Moreover, this allowed the MIPs to better facilitate by combining the template molecules, as well as optimizing the imprinting factor. In addition, after 80 min, the adsorption of the MIPs leveled off and remained constant, and the adsorption quantity reached (a maximum of) at 8.1 mg·g−1.

scholarly journals How to manipulate the upper critical solution temperature (UCST)?

2017 ◽  
Vol 8 (1) ◽  
pp. 220-232 ◽  
Author(s):  
Jukka Niskanen ◽  
Heikki Tenhu
Keyword(s):  
Aqueous Solutions ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Critical Solution Temperature ◽  
Stimuli Responsive Polymers ◽  
Responsive Polymers ◽  
Ph Influence ◽  
Counter Ions ◽  
Upper Critical Solution Temperature

In this mini-review, we discuss multi-stimuli-responsive polymers, which exhibit upper critical solution temperature (UCST) behavior mainly in aqueous solutions, and focus on examples where counter ions, electricity, light, or pH influence the thermoresponsiveness of these polymers.

scholarly journals Microfluidics of Binary Liquid Mixtures with Temperature-Dependent Miscibility

2019 ◽  
Author(s):  
Maximiliano J. Fornerod ◽  
Esther Amstad ◽  
Stefan Guldin
Keyword(s):  
Phase Separation ◽  
Flow Regimes ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Solution Temperature ◽  
Microfluidic Channels ◽  
Temperature Sensitive ◽  
Critical Solution Temperature ◽  
Binary Liquid ◽  
Sensing Applications

Liquid-liquid microfluidic systems rely on the intricate control over the fluid properties of either miscible or immiscible mixtures. Herein, we report on the use of partially miscible binary liquid mixtures that lend their microfluidic properties from a highly temperature-sensitive mixing and phase separation behaviour. For a blend composed of the thermotropic liquid crystal 4-Cyano-4'-pentylbiphenyl (5CB) and methanol, mixing at temperatures above the upper critical solution temperature (UCST; 24.4°C) leads to a uniform single phase while partial mixing can be achieved at temperatures below the UCST. Thermally-driven phase separation inside the microfluidic channels results in the spontaneous formation of very regular phase arrangements, namely in droplets, plug, slug and annular flow. We map different flow regimes and relate findings to the role of interfacial tension and viscosity and their temperature dependence. Importantly, different flow regimes can be achieved at constant channel architecture and flow rate by varying the temperature of the blend. A consistent behaviour is observed for a binary liquid mixture with lower critical solution temperature, namely 2,6-lutidine and water. This temperature-responsive approach to microfluidics is an interesting candidate for multi-stage processes, selective extraction and sensing applications.

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