Online, continuous monitoring of the sensitivity of the LCST of NIPAM-Am copolymers to discrete and broad composition distributions

McFaul, Colin A.; Drenski, Michael F.; Reed, Wayne F.

doi:10.1016/j.polymer.2014.08.004

Cited by 13 publications

(10 citation statements)

References 25 publications

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“…This was used to study the effects on the lower critical solution temperature (LCST) of copolymerizing n-isopropyl acrylamide (NIPAM) with more hydrophilic comonomers [52,53].…”

Section: Second Generation Acomp (Sga) For Monitoring the Synthesis Omentioning

confidence: 99%

Simultaneous Monitoring of the Effects of Multiple Ionic Strengths on Properties of Copolymeric Polyelectrolytes during Their Synthesis

Zhu

Drenski³

et al. 2017

Processes

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Abstract:A new Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) system has been developed with multiple light scattering and viscosity detection stages in serial flow, where solution conditions are different at each stage. Solution conditions can include ionic strength (IS), pH, surfactants, concentration, and other factors. This allows behavior of a polymer under simultaneous, varying solution conditions to be monitored at each instant of its synthesis. The system can potentially be used for realtime formulation, where a solution formulation is built up additively in successive stages. It can also monitor the effect of solution conditions on stimuli responsive polymers, as their responsiveness changes during synthesis. In this first work, the new ACOMP system monitored light scattering and reduced viscosity properties of copolymeric polyelectrolytes under various IS during synthesis. Aqueous copolymerization of acrylamide (Am) and styrene sulfonate (SS) was used. Polyelectrolytes in solution expand as IS decreases, leading to increased intrinsic viscosity (η) and suppression of light scattering intensity due to electrostatically enhanced second and third virial coefficients, A 2 and A 3 . At a fixed IS, the same effects occur if polyelectrolyte linear charge density (ξ) increases. This work presents polyelectrolyte response to a series of IS and changing ξ during chemical synthesis.Keywords: ACOMP; online monitoring; copolymeric polyelectrolytes; light scattering; viscosity Background and MotivationThis work introduces a new version of the Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) system ("second generation ACOMP") whose aim is to monitor the onset and evolution of stimuli responsive behavior, under multiple simultaneous solution conditions, during the synthesis of stimuli responsive polymers (SRP). SRP is a vast area of modern polymer science and engineering, aimed at producing polymers that can respond to such stimuli as temperature, radiation, and solution conditions such as pH, ionic strength, polymer concentration, presence of such agents as surfactants, nanoparticles, hydrophobic species, etc. The types of responses that can occur in response to these stimuli include coil/globule phase transitions, polymer coil expansion or shrinkage, micellization, aggregation, and other forms of spontaneous self-assembly.These next-generation materials are expected to have applications in medicine, sensors, self-healing materials, and environmental remediation [1][2][3][4][5]. Hydrogels ofpoly(N-isopropylacrylamide), for example, have a lower critical solution temperature (LCST), near body temperature, which makes it a candidate for drug delivery applications in which the NIPAM-based polymer releases its medical

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“…This was used to study the effects on the lower critical solution temperature (LCST) of copolymerizing n-isopropyl acrylamide (NIPAM) with more hydrophilic comonomers [52,53].…”

Section: Second Generation Acomp (Sga) For Monitoring the Synthesis Omentioning

confidence: 99%

Simultaneous Monitoring of the Effects of Multiple Ionic Strengths on Properties of Copolymeric Polyelectrolytes during Their Synthesis

Zhu

Drenski³

et al. 2017

Processes

View full text Add to dashboard Cite

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“…A majority of the polymers in these areas of application are thermo‐responsive with regards to their solubility, such as polymers that exhibit a lower critical solution temperature (LCST) as a means to impart conformational molecular changes simply by applying a thermal stimulus 12,16–19 . Over a defined temperature range, these solution‐state polymers demonstrate a characteristic change from random coils to collapsed coacervates, which are more condensed, globule‐like structures., 12,15–21 In order to increase the range of applications for such polymers, it becomes increasingly important to predict and control their LCST, 14,19 which has traditionally been achieved through the addition of salts or comonomers 12,17,22–24 …”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…One particular polymer of interest is poly( N ‐isopropylacrylamide) (PNIPAM), because it has an LCST of approximately 32°C, close to the average human body temperature of 37°C, making it attractive for biological applications 19,21 . The manipulation in the LCST of polymers containing N ‐isopropylacrylamide (NIPAM) has been well established and reported with changes in molecular weight, molecular weight distribution, composition, tacticity, and topology 2,19–21,25–34 . At temperatures below the LCST, NIPAM is more hydrophilic and miscible in aqueous solutions; however, at temperatures greater than the LCST, the amide and isopropyl groups have significantly reduced coordination with water molecules 17–20 .…”

Section: Introductionmentioning

confidence: 99%

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Exploring polymer solubility with thermally‐responsive Diels‐Alder monomers: Revisiting the monkey's fist

Bisbjerg

Brown

Pham

et al. 2021

Journal of Polymer Science

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Thermo‐responsive monomers were designed to contain a Diels‐Alder (DA) adduct such that cyclo‐reversion would yield either the maleimide or the furan unit attached to the polymer chain. These thermally responsive monomers were then copolymerized with N‐isopropylacrylamide (NIPAM) via reversible addition‐fragmentation chain‐transfer (RAFT) polymerization to yield linear gradient‐copolymer structures as a comparison to existing nanogel/starlike systems to understand how polymer topology and composition influence solution‐state properties. Using UV–Vis spectroscopy, it was determined that solution‐state properties were thermally dependent and influenced by a number of variables such as comonomer feed ratio, polymer chain end functionality, and polymer backbone length and composition. Manipulation of the feed ratio allowed for control over the cloud point, including the breadth and location of phase separation. Thermal treatment of these copolymers revealed tunable and predictable variations in previously observed transitions, directly correlated to cleavage of the DA adducts and change in polymer backbone composition. Finally, on cooling cycles, a double sigmoid was sometimes observed, indicating a complex globule to random coil transition correlated to polymer chain end composition. These studies help understand how to untie the “monkey's fist.”

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“…[15][16][17][18] Different control systems for online reaction monitoring systems (ORMSs) have been reported: manually operated reactor systems using buttons directly on the devices 6,19 and individually controlled system components using in-house software 5 or software modules written in LABVIEW. 20,21 At a higher control level, automatic control solutions using feedback data from the analyzer have been applied, whereby the control algorithms are usually realized in MATLAB. [22][23][24] Furthermore, a modular software system operating via Internet is presented for monitoring chemical reactions, control, and autonomously self-optimizing the reaction parameters.…”

Section: Introductionmentioning

confidence: 99%

Online Measurement System in Reaction Monitoring for Determination of Structural and Elemental Composition Using Mass Spectrometry

2019

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The monitoring of chemical reactions is an important task in chemical engineering, especially in quality control, pharmaceutical and biological processes, or industrial production. The development of new reactions such as catalyst-based procedures requires detailed knowledge about process steps and reaction kinetics. For qualitative and quantitative analysis of reactants and resulting products, proprietary online measurement systems are used, which were designed for special applications. A mobile online reaction monitoring system was developed for a flexible coupling to different mass selective measurement systems for structural (ESI-MS) and elemental (ICP-MS) analysis to determine chemical precursors, reaction products, and internal standard compounds and their elemental composition at any stage of the reaction. Chemical reactions take place in a tempered continuous-flow microreactor. The flow rate in the microreactor can be varied to adjust the residence times in the reactor. An online dilution module was integrated to adapt the concentration of the reaction solutions to the working range of the analyzers. The performance and limitations of the online reaction system were determined using standard solutions and a real chemical reaction. The control software with a graphical user interface enables the adjustment of reaction, sampling, and measurement parameters as well as the system and process control.

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Online, continuous monitoring of the sensitivity of the LCST of NIPAM-Am copolymers to discrete and broad composition distributions

Cited by 13 publications

References 25 publications

Simultaneous Monitoring of the Effects of Multiple Ionic Strengths on Properties of Copolymeric Polyelectrolytes during Their Synthesis

Simultaneous Monitoring of the Effects of Multiple Ionic Strengths on Properties of Copolymeric Polyelectrolytes during Their Synthesis

Exploring polymer solubility with thermally‐responsive Diels‐Alder monomers: Revisiting the monkey's fist

Online Measurement System in Reaction Monitoring for Determination of Structural and Elemental Composition Using Mass Spectrometry

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