The effect of nanoparticle location and shape on thermal transitions observed in hydrated layer-by-layer assemblies

Soft Matter ◽  
2014 ◽  
Vol 10 (40) ◽  
pp. 8107-8115 ◽  
Author(s):  
Joseph T. Puhr ◽  
Benjamin E. Swerdlow ◽  
Dariya K. Reid ◽  
Jodie L. Lutkenhaus
Keyword(s):  
Thermal Transition ◽  
Layer By Layer ◽  
Thermal Transitions ◽  
Lbl Assembly ◽  
Hydrated Layer ◽  
Higher Temperature

When nanoparticles are inserted at different locations within a layer-by-layer (LbL) assembly, a second higher temperature thermal transition appears under select conditions.

Thermal transitions in hydrated layer-by-layer assemblies observed using electrochemical impedance spectroscopy

Soft Matter ◽  
2014 ◽  
Vol 10 (34) ◽  
pp. 6467-6476 ◽  
Author(s):  
Choonghyun Sung ◽  
Katelin Hearn ◽  
Jodie Lutkenhaus
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Thermal Transition ◽  
Layer By Layer ◽  
Thermal Transitions ◽  
Transfer Resistance ◽  
Hydrated Layer

Layer-by-layer assemblies exhibit increased conductivity and decreased charge transfer resistance upon heating through the thermal transition.

Thermal Transitions in Dry and Hydrated Layer-by-Layer Assemblies Exhibiting Linear and Exponential Growth

ACS Nano ◽  
2012 ◽  
Vol 6 (7) ◽  
pp. 6174-6184 ◽  
Author(s):  
Ajay Vidyasagar ◽  
Choonghyun Sung ◽  
Randall Gamble ◽  
Jodie L. Lutkenhaus
Keyword(s):  
Exponential Growth ◽  
Layer By Layer ◽  
Thermal Transitions ◽  
Hydrated Layer

pH-Dependent Thermal Transitions in Hydrated Layer-by-Layer Assemblies Containing Weak Polyelectrolytes

2012 ◽  
Vol 45 (22) ◽  
pp. 9169-9176 ◽  
Author(s):  
Ajay Vidyasagar ◽  
Choonghyun Sung ◽  
Kristen Losensky ◽  
Jodie L. Lutkenhaus
Keyword(s):  
Layer By Layer ◽  
Thermal Transitions ◽  
Hydrated Layer ◽  
Ph Dependent ◽  
Weak Polyelectrolytes

scholarly journals Encapsulation of Phase Change Materials Using Layer-by-Layer Assembled Polyelectrolytes

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Qiangying Yi ◽  
Gleb B. Sukhorokov ◽  
Jin Ma ◽  
Xiaobo Yang ◽  
Zhongwei Gu
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Low Cost ◽  
Sodium Dodecyl ◽  
Layer By Layer ◽  
Latent Heat Storage ◽  
Good Thermal Stability ◽  
Lbl Assembly ◽  
Acid Sodium Salt ◽  
Assembly Technique

Phase change materials absorb the thermal energy when changing their phases (e.g., solid-to-liquid) at constant temperatures to achieve the latent heat storage. The major drawbacks such as limited thermal conductivity and leakage prevent the PCMs from wide application in desired areas. In this work, an environmentally friendly and low cost approach, layer-by-layer (LbL) assembly technique, was applied to build up ultrathin shells to encapsulate the PCMs and therefore to regulate their changes in volume when the phase change occurs. Generally, the oppositely charged strong polyelectrolytes Poly(diallyldimethylammonium chloride) (PDADMAC) and Poly(4-styrenesulfonic acid) sodium salt (PSS) were employed to fabricate multilayer shells on emulsified octadecane droplets using either bovine serum albumin (BSA) or sodium dodecyl sulfate (SDS) as surfactant. Specifically, using BSA as the surfactant, polyelectrolyte encapsulated octadecane spheres in size of ∼500 nm were obtained, with good shell integrity, high octadecane content (91.3% by mass), and good thermal stability after cycles of thermal treatments.

scholarly journals Electrical Field-Assisted Gene Delivery from Polyelectrolyte Multilayers

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 133
Author(s):  
Yu-Che Cheng ◽  
Shu-Lin Guo ◽  
Kun-Da Chung ◽  
Wei-Wen Hu
Keyword(s):  
Gene Delivery ◽  
Electric Field ◽  
Treatment Time ◽  
Transfection Efficiency ◽  
Polyelectrolyte Multilayers ◽  
Aqueous Environment ◽  
Layer By Layer ◽  
Electrical Field ◽  
Lbl Assembly ◽  
Electric Field Treatment

To sustain gene delivery and elongate transgene expression, plasmid DNA and cationic nonviral vectors can be deposited through layer-by-layer (LbL) assembly to form polyelectrolyte multilayers (PEMs). Although these macromolecules can be released for transfection purposes, their entanglement only allows partial delivery. Therefore, how to efficiently deliver immobilized genes from PEMs remains a challenge. In this study, we attempt to facilitate their delivery through the pretreatment of the external electrical field. Multilayers of polyethylenimine (PEI) and DNA were deposited onto conductive polypyrrole (PPy), which were placed in an aqueous environment to examine their release after electric field pretreatment. Only the electric field perpendicular to the substrate with constant voltage efficiently promoted the release of PEI and DNA from PEMs, and the higher potential resulted in the more releases which were enhanced with treatment time. The roughness of PEMs also increased after electric field treatment because the electrical field not only caused electrophoresis of polyelectrolytes and but also allowed electrochemical reaction on the PPy electrode. Finally, the released DNA and PEI were used for transfection. Polyplexes were successfully formed after electric field treatment, and the transfection efficiency was also improved, suggesting that this electric field pretreatment effectively assists gene delivery from PEMs and should be beneficial to regenerative medicine application.

scholarly journals Fabrication of thermo-regulating cotton fabric with enhanced flame retardancy via layer-by-layer assembly

2021 ◽  
Author(s):  
Yunbo Chen ◽  
Xiangyu Zhu ◽  
Xiang Li ◽  
Bijia Wang ◽  
Zhiping Mao ◽  
...  
Keyword(s):  
Flame Retardancy ◽  
High Performance ◽  
Cotton Fabrics ◽  
Melting Enthalpy ◽  
Residual Carbon ◽  
Layer By Layer ◽  
Scanning Calorimetry ◽  
Infrared Thermal Imaging ◽  
Limiting Oxygen Index ◽  
Lbl Assembly

Abstract The lack of thermo-regulation functionality and high flammability of cotton fabrics greatly restrict their application in high-performance fields. Herein, we report a versatile layer-by-layer (LbL) assembly strategy for introducing to cotton fabrics a multilayered coating consisted of phase change microcapsules and ammonium polyphosphate, endowing them with thermo-regulating and flame retardancy. The coated fabrics were characterized by limiting oxygen index (LOI), scanning electron microscopy (SEM), thermogravimetry (TG), differential scanning calorimetry (DSC) and infrared thermal imaging. The fabric deposited with 20 bilayers (MCPM/APP-20) showed improved flame retardancy with a LOI of 24.4% and residual carbon of 34.24%. It also shows a melting enthalpy of 30.16 J/g, which transferred to a temperature difference of 6.4 ℃ compared with pristine cotton. The functional endowed by the LbL assembly was reasonably durable, with melting enthalpy and residual carbon of MPCM/APP-20 reduced to 17.14 J/g and 19.82% after 30 laundering cycles. These results suggest that LbL assembly was a convenient way for functionalization of cotton fabrics.

Self-Assembly of Alkali Lignin in Tetrahydrofuran

2012 ◽  
Vol 550-553 ◽  
pp. 57-61
Author(s):  
Hao Li ◽  
Yong Hong Deng ◽  
Kai Huang
Keyword(s):  
Charge Transfer ◽  
Electrostatic Interaction ◽  
Self Assembly ◽  
The Self ◽  
Charge Transfer Complexes ◽  
Layer By Layer ◽  
Alkali Lignin ◽  
Higher Temperature ◽  
Effects Of Temperature

Alkali lignin (AL) was used as a polyanion to form layer-by-layer self-assembled film with PDAC as a polycation. The effects of temperature and concentration on the adsorption characteristics of AL were investigated. Iodine was added into AL solutions to study the role of π-π interaction in self-assembly of AL and PDAC. Results show that the self-assembly of AL/PDAC is mainly driven by π-π interaction and electrostatic interaction. A higher temperature or a larger concentration can enhance the aggregation of lignin. I2 can form lignin–iodine charge–transfer complexes with AL to reduce the degree of aggregation of AL, so the adsorbed amount of AL decreases significantly with increasing iodine contents.

Few durable layers suppress cotton combustion due to the joint combination of layer by layer assembly and UV-curing

RSC Advances ◽  
2015 ◽  
Vol 5 (87) ◽  
pp. 71482-71490 ◽  
Author(s):  
Federico Carosio ◽  
Jenny Alongi
Keyword(s):  
Flame Retardancy ◽  
Uv Curing ◽  
Layer By Layer ◽  
Lbl Assembly ◽  
Layer By Layer Assembly ◽  
Innovative Solutions ◽  
Layer Assembly

In the last five years, Layer by Layer (LbL) assembly has proven to be one of the most innovative solutions for conferring flame retardancy to fabrics.

Electric-field induced layer-by-layer assembly technique with single component for construction of conjugated polymer films

RSC Advances ◽  
2015 ◽  
Vol 5 (72) ◽  
pp. 58499-58503 ◽  
Author(s):  
Shiwei Wang ◽  
Zhuo Chen ◽  
Ahmad Umar ◽  
Yao Wang ◽  
Peng-gang Yin
Keyword(s):  
Electric Field ◽  
Conjugated Polymer ◽  
Multilayer Films ◽  
Single Component ◽  
Layer By Layer ◽  
Lbl Assembly ◽  
Layer By Layer Assembly ◽  
Universal Approach ◽  
Assembly Technique ◽  
Layer Assembly

Single component was used to construct conjugated polymer multilayer films by electric-field induced layer-by-layer assembly technique, which provides a universal approach for CPs and broadens the applicable scope of LBL assembly technique.

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