高分子に閉じ込められた水の水素結合状態と動的性質に対する分子動力学解析
Revealing the hidden dynamics of confined water in acrylate polymers:
Insights from hydrogen-bond lifetime analysis
四方志1, 菊辻卓真1, 八十島亘宏1, 金鋼1, 松林伸幸1

1 阪大院基礎工

Introduction✽ Background✽ Simulation systems

PMEA : poly(2-methoxyethyl acrylate)FWØBlood Compatibility Polymer
prevents blood clots formation

ndesorpadsorpl PMEAl PHEMAl PMC1Ann

interaction
with PMEA

proteinIWnO2

l Experiments with DSC: Freeze at 0 ℃→ Free water (FW)•: Freeze at ‒ 40 ℃
→ Intermediate water (IW)Ø Hydration structure in PMEA

Definition of H-bondWater molecules inserted into 20 polymers :3 wt% ~ 90 wt%

PHB (t) =kB T ln g(roo , )w

Dynamic properties of water moleculesin PMEA can be classified according to
the acceptor oxygen

Water O - Water O

3n2O2O1✽ H-bond lifetime

040𝑖donor H

Z 1<latexit sha1_base64="fOcfOerAXZYfNNUcIL8esqgMrxw=">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</latexit>

-3
0.2

0.3

0.4

0.5

0.6𝑟!!

0.7roo [nm]𝛽⌧HB =𝑗Integration of 𝑃%&

Ø Difference of 𝜏%& between each acceptors
Ø Converge to a constant value

Water Ow - Ether like O2roo  0.35 nm

10032Ester like oxygen : O2
does not make H-bond.

β [degree]80

 30

10.8

0.80.80.6(c) PMC1A

0.6

0.6

0.4

0.4

0.4

0.2

0.2

0.2

010-310-210-1 100 101 102 103 104 105

010-310-210-1 100 101 102 103 104 105

010-310-210-1 100 101 102 103 104 105

t [ps](b) PHEMAt [ps](c) PMC1A

1051051041041010= Time constant to break H-bondü H-bond region

0PHB (t)dt

0acceptor O<latexit sha1_base64="wdPcyefkjABAsMxAV2DCfgkgdKY=">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</latexit>

1(a) PMEA-20(b) PHEMA

1t [ps]τHB [ps]β [degree]

O360-1hhi,j (t)hi,j (0)ihhi,j (0)iPHB<latexit sha1_base64="3/Cf91VSofVNHffLxYihAxNpNjk=">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</latexit>(a) PMEAPHB✽ Time correlation function<latexit sha1_base64="zTauhlkJczxaE57AT2o7QoRw/eU=">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</latexit>

20

Production run : Max 500 ns (NVT)

Dynamical properties of water

Determined by free energy surface :Distribution of distance and angle
between water and each oxygen

1poly(1-methoxy methyl acrylate)• Water molecule behavior is not organized.

We analyzed the H-bond dynamics in polymer;
understand the properties of the water moleculesin PMEA by MD simulations.

80poly(2-hydroxyethylmeth acrylate)• polymer : OPLS-AA Force Field, 50mer, atactic• water: TIP4P/2005 model• Predictions from thermal experiments

100O2H

Only PMEA has intermediate water
Saturated moisture content in experiment of PMEA : 9 wt%

Expectedhydration
structure→ Nonfreezing water (NFW)

wO1O2O3poly(2-methoxy ethyl acrylate)• ‒110 ℃ without freezing

W (roo , ) =O1O3O3•

Tanaka, M., et al., Polymer International, 49(12), 1709 (2000)

O2103
102

54

τHB [ps]water content

O1NFW: three kinds of water

PHBO3

τHB [ps]

O1103
102

101

101

100

100

103
102
101

160

Lifetime : O1 > O3 > Ow ≈ bulk water040-120

In all systems :-20

10 20 30 40 50 60 70 80 90

0.2

0.3

0.4

0.5

0.6

Mobility depends on moisture content

0.7roo [nm]10 20 30 40 50 60 70 80 90

wt%

-3100

10 20 30 40 50 60 70 80 90

wt%

Carbonyl O1

wt%

Methoxy or Hydroxy O3

Water Ow

Stability of H-bond and state of water existenceh(t) =(<latexit sha1_base64="Td4kwQI+eKn94mL9wIq+tuYcuus=">AAADAnichZHPa9RAFMdfUrV1/dFVL4KXwaXLLkh4aesPBKXgpcf+cNtCpyxJdjY7dDIJyexCDXvz5D/gQTwoiKgn8erNi/+Ah/4J4rGCFw++ZCNF1x8vZObNd97nvTczfqJkZhAPLXvmxMlTs3Ona2fOnjs/X79wcSuLh2kgOkGs4nTH9zKhpBYdI40SO0kqvMhXYtvfv1fsb49EmslY3zcHidiLvFDLvgw8Q1K3/nS1ZdrsDuNK9A3Pa4yM+yKUOveUDLXojUutyVzGrzVbaZdHnhmkUR7H44Ji6CxdZz9FHY3bjPMKwT8gd6eBSVGhe8cleSrDgXG69QY6WBqbdtzKaUBla3H9JXDoQQwBDCECARoM+Qo8yOjbBRcQEtL2ICctJU+W+wLGUCN2SFGCIjxS92kMabVbqZrWRc6spAOqouhPiWSwgJ/wFR7hR3yDn/H7X3PlZY6ilwOa/Qkrku78o8ub3/5LRTQbGBxT/+zZQB9ulb1K6j0pleIUwYQfPXh8tHl7YyFv4nP8Qv0/w0P8QCfQo6/Bi3Wx8QRq9ADu79c97WwtOu4Nx11fbqwsV08xB1fgKrTovm/CCqzCGnQgsGastrVoLdkP7df2W/vdJNS2KuYS/GL2+x+YE7vW</latexit>

1(H Bond)

0(not H Bond)𝑡 = 0 : H-Bondedh(t))H(t)ihh(0)i
H(t) =(10𝑡 = 𝑡 : not H-bondedn(roo  0.35nm)

nO2(roo > 0.35nm)

OO2

1O

1O3after 𝑡• Long time region :𝑁 𝑡 is decayed, diffused• Peak near H-bond lifetime𝑟!! < 0.35 nm
𝛽 > 30°𝑟!! < 0.35 nm
𝛽 < 30°(b) PHEMA(a) PMEA(b) PHEMA(c) PMC1A
0.4

0.3

0.3

0.3

0.1

N(t)

0.4

N(t)

0.4

0.2
0.1

80
60
40
200100101

102

40
200100101102

103

104

80
60
40
200100101102

103

104

The size of water cluster [molecules] The size of water cluster [molecules] The size of water cluster [molecules]
6 wt%

9 wt%

12 wt%

15 wt%

20 wt%

25 wt%

30 wt%

at 3 wt% : ~ 10 molecules
more than 20 wt% :almost all water in the system

Analyzed dynamic properties of water in polymers

0.1
010-3 10-2 10-1 100 101 102 103 104 105

t [ps]t [ps]t [ps]
30 wt%

10460

Ø Small clusters reduce water mobility

010-3 10-2 10-1 100 101 102 103 104 105

9 wt%

103

100

80

0.2

010-3 10-2 10-1 100 101 102 103 104 105

3 wt%(c) PMC1A

100

3 wt%

Ø The conditional probability of water molecule and acceptor remain in close
at time 𝑡 after H-bond breakage, given they were H-bonded at 𝑡 = 0.

N(t)(a) PMEA
100O30.2

Accumulated percentage of water clusterʼs size
using H-bond length

percentage [%]<latexit sha1_base64="4sydakcP8A6ZjCr3gRXmyFmmUyw=">AAAC6HichVHPaxNBFH67aq3RNlEvFS+DoSGFEmal2CIIRS899odpC50Sdjcvm2lmZ5fdSaAuOXnz5K2IJwsi4p/RS/8BD/0TiscKXjz4slkItWjfMDNvvvm+N9/MeLGSqeH8zLJv3Lw1dXv6TunuvZnZcuX+g+006ic+Nv1IRcmu56aopMamkUbhbpygG3oKd7zeq9H+zgCTVEb6tTmMcT90Ay070ncNQa3K227dLLAXTCjsGJGVGIXwMJA6c5UMNLaHOVZjDhOLNRG6ppuEWX1NLLKXkW4vDJkQBYNfYujIEGfCG5dG3Z4UFokMuqbRqlR5g+fBriZOkVShiPWo8gUEtCECH/oQAoIGQ7kCF1Jqe+AAh5iwfcgISyiT+T7CEEqk7RMLieES2qMxoNVegWpaj2qmudqnUxT1hJQM5vl3/pVf8FP+jZ/z3/+sleU1Rl4OafbGWoxb5XdzW7+uVYU0G+hOVP/1bKADK7lXSd7jHBndwh/rB2+OLraeb85nNX7Mf5D/T/yMn9AN9OCn/3kDNz9CiT7A+fu5rybbTxvOs4azsVRdXSq+YhoewxOo03svwyqswTo06dxzq2zNWY/sA/u9fWR/GFNtq9A8hEthH/8BD8yySw==</latexit>

hh(0)(1percentage [%]<latexit sha1_base64="gS8WyQY/QNKF10QVW03zYiCB6Rw=">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</latexit>

N (t) =

✽ Cluster sizepercentage [%]✽ Diffusion of water and H-bond breakage

90 wt%A unique state was observed in O3 at PMEAIn short time region :PMEA … Large 𝑁 𝑡 , no diffusion after H-bonds breakage
Others … Small 𝑁 𝑡 , still H-bonding• H-bond lifetime can be classified by acceptor oxygen• Water content governs mobility• Interaction of PMEA with methoxy oxygen :Intermediate strength interactions
Reference : K. Shikata, et al., J. Chem. Phys. 158, 174901 (2023).