國立虎尾科技大學 |

The development and characterization of stimuli-responsive systems for performance materials.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	The development and characterization of stimuli-responsive systems for performance materials./
Author:	Gordon, Melissa B.
Description:	1 online resource (225 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-08(E), Section: B.
Subject:	Chemical engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9781369681079

The development and characterization of stimuli-responsive systems for performance materials.
Gordon, Melissa B.

The development and characterization of stimuli-responsive systems for performance materials. - 1 online resource (225 pages)

Source: Dissertation Abstracts International, Volume: 78-08(E), Section: B.

Thesis (Ph.D.)--University of Delaware, 2017.

Includes bibliographical references

In nature, living organisms adjust to their surroundings by responding to environmental cues, such as light, temperature or force. Stimuli-triggered processes, such as the contraction of eyes in response to bright light or wound healing in skin after a cut, motivate the design of "smart" materials which are designed to respond to environmental stimuli. Responsive materials are used as self-healing materials, shape memory polymers and responsive coatings; moreover, responsive materials may also be employed as model systems, which enhance understanding of complex behavior.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369681079Subjects--Topical Terms:

555952
Chemical engineering.
Index Terms--Genre/Form:

554714
Electronic books.

The development and characterization of stimuli-responsive systems for performance materials.
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100 1 $a Gordon, Melissa B. $3 1187150
245 1 4 $a The development and characterization of stimuli-responsive systems for performance materials.
264 0 $c 2017
300 $a 1 online resource (225 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
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500 $a Source: Dissertation Abstracts International, Volume: 78-08(E), Section: B.
500 $a Advisers: Christopher J. Kloxin; Norman J. Wagner.
502 $a Thesis (Ph.D.)--University of Delaware, 2017.
504 $a Includes bibliographical references
520 $a In nature, living organisms adjust to their surroundings by responding to environmental cues, such as light, temperature or force. Stimuli-triggered processes, such as the contraction of eyes in response to bright light or wound healing in skin after a cut, motivate the design of "smart" materials which are designed to respond to environmental stimuli. Responsive materials are used as self-healing materials, shape memory polymers and responsive coatings; moreover, responsive materials may also be employed as model systems, which enhance understanding of complex behavior.
520 $a The overall goal of this work is to design a material that offers self-healing functionality, which will allow for self-repair following material fatigue or failure, and increased strength in response to ballistic or puncture threats through the incorporation of colloidal particles. The target application for this material is as a protective barrier in extreme environments, such as outer space. Towards this end, the dissertation is focused on the development and characterization of each component of the protective material by (1) designing and testing novel light- and force-sensitive polymers for self-healing applications and (2) examining and characterizing long-time behavior (i.e., aging) in model thermoreversible colloidal gels and glasses.
520 $a Towards the development of novel stimuli-responsive materials, a photo-responsive polymer network is developed in which a dynamic bond is incorporated into the network architecture to enable a light-triggered, secondary polymerization, which increases the modulus by two orders of magnitude while strengthening the network by over 100%. Unlike traditional two-stage polymerization systems, in which the secondary polymerization is triggered by a leachable photoinitiator, the dynamic nature is imparted by the material itself via the dissociation of its own crosslinks to become stronger in response to light. Several attributes of the photo-responsive network are shown including: (1) photo-induced healing and strengthening of a specimen after it has been severed, (2) photopatterning for effecting spatially confined property changes on demand, and (3) locking in the film's 3D geometry using light after reshaping. The utility of the photo-responsive dynamic bond is enhanced by demonstrating that it is also responsive to mechanical force. Force-responsive materials are activated by the energy from the damage event itself, thereby enabling healing without human intervention. Specifically, selective cleavage of a polymer containing a dynamic trithiocarbonate group initiates a force-driven radical polymerization, thus enabling the material to constructively respond to force via gelation on an experimentally relevant timescale.
520 $a To enhance the stress response of the self-healing materials described above, a protective material composed of colloidal particles is proposed. Toward this goal, the second half of this dissertation investigates the microstructural basis of rheological aging in colloidal gels and glasses using a model thermoreversible colloidal dispersion. In this work, rheological aging is quantitatively related to microstructural aging in glasses and gels by simultaneously measuring the bulk properties and sample microstructure using rheometry and small angle neutron scattering (Rheo-SANS), respectively. A one-to-one correspondence between the evolution in storage modulus and microstructure as the sample ages is observed, which is investigated as a function of thermal and shear history. The microstructural measurements are consistent with the hypothesis of aging as a trajectory in a free energy landscape, which combined with analysis with mode coupling theory, support local particle rearrangements as the mechanism of aging. Moreover, by using a system that is fully rejuvenated by thermal cycling, the effectiveness of shear as a rejuvenation method is investigated by directly comparing microstructure and bulk properties following thermal and mechanical rejuvenation. The conclusions of this study may be industrially relevant to products that age on commercial timescales, such as pharmaceuticals, applicable to other dynamically arrested systems, such as metallic glasses, and provide pathways to advanced composite materials such as those envisioned in this work.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Chemical engineering. $3 555952
650 4 $a Materials science. $3 557839
655 7 $a Electronic books. $2 local $3 554714
690 $a 0542
690 $a 0794
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a University of Delaware. $b Department of Chemical Engineering. $3 1187151
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10255334 $z click for full text (PQDT)