Tensile properties of two responsive hydrogels

Hinkley, Jeffrey A.; Morgret, Leslie D.; Gehrke, Stevin H.

doi:10.1016/j.polymer.2004.09.088

Cited by 48 publications

(25 citation statements)

References 34 publications

(40 reference statements)

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“…NIPAM has been most widely discussed but other aqueous gels are also thermally responsive, including poly N-vinylcaprolactam (PVCL) and hydroxypropylcellulose (HPC) [99]. In the unswollen (high temperature) state, PVCL is much stiffer than in the swollen state and resembles a glassy polymer, whereas in HPC the modulus decreases as it shrinks.…”

Section: Thermally Driven Gel Actuatorsmentioning

confidence: 99%

See 1 more Smart Citation

Polymer Gel Actuators: Fundamentals

Calvert

2009

Biomedical Applications of Electroactive Polymer Actuators

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One view of materials development is to search for what materials correspond to empty spaces on a hypothetical multi-dimensional map of the properties of available materials. Following a biomimetic philosophy, for instance, it can be seen that tough ceramics and moldable short fiber composites with high moduli are possible but absent from the list of available synthetic materials. Likewise artificial muscle is missing, where the properties are defined as a developed stress of over 300 kPa, a linear contraction of 25 % and a response time of below one second. Currently dielectric elastomers come closest but have disadvantages [1,2].The actin-myosin muscle system provides the performance target for electroactive polymer actuators [3,4]. The process is driven chemically by the energy change from hydrolysis of the polyphosphate bond as ATP (adenosine triphosphate) binds to myosin and is converted to ADP (adenosine diphosphate) and phosphate. A simple chemical analogy suggests that muscle-like gels should be feasible but it is now clear that the task is much harder than it seems.Early work on gel actuation by Katchalsky-Katzir demonstrated that engines could be built using the chemical energy in diluting a lithium bromide solution to drive contraction and expansion of a collagen belt [5]. In essence, the collagen expands to take up the salt solution or contract to exclude the water. This change is both a molecular conformation change and a volume change. Other chemically driven gels, for instance polyacrylic acid fibers [6] which respond to a pH change, also rely on a solubility change giving rise to a volume change.

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Section: Thermally Driven Gel Actuatorsmentioning

confidence: 99%

“…Hinkley et al report an estimated maximum work achievable by the thermally driven PVCL gels of 1 MJ.m -3 of dry gel, considerably higher than that for poly(vinyl alcohol) gels and comparable with muscle [99]. However, the response is very slow.…”

Section: Performance Of Gels As Actuatorsmentioning

confidence: 99%

Polymer Gel Actuators: Fundamentals

Calvert

2009

Biomedical Applications of Electroactive Polymer Actuators

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“…Because of their environmental sensitivity and unique structure, these polymeric hydrogels have been investigated for many biomedical and pharmaceutical applications including drug delivery systems, separation techniques, musclelike actuators, and construction of sensors [4][5][6][7][8]. Among these intelligent polymers, pH-and temperature-sensitive hydrogels are the most widely investigated.…”

Section: Introductionmentioning

confidence: 99%

Swelling behavior of polyacrylamide/laponite clay nanocomposite hydrogels: pH-sensitive property

Kim

Siddaramaiah

et al. 2009

Composites Part B: Engineering

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“…HPC has also been reacted with divinyl sulfone at high pH (pH~12) to form a temperature-responsive hydrogel which shrinks upon warming. This system was investigated for its potential to serve as an actuator or "artificial muscle" (Hinkley et al 2004). In addition to divinyl sulfone and PEG/vinyl sulfone, vinyl sulfone macromers have also been produced.…”

Section: Direct Cross-linking Methodsmentioning

confidence: 99%